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Biochem First aid > Metabolism > Flashcards

Metabolism Flashcards

0
Q

What does kwashiorkor look like?

A

Child with a swollen belly

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1
Q

What is mneumonic for Kwashiorkor?

A

Malnutrition
Edema
Anemia
Liver change (fatty -from decreased synthesis of apolipoprotein)

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2
Q

What is marasmus?

A

Energy malnutrition resulting in tissue muscle wasting, loss of subcutaneous fat, edema

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3
Q

What is the difference between marasmus and kwashiorkor?

A

They have enough calories but lack protein in kwashiorkor.

They lack calories altogether in marasmus

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4
Q

What metabolism happens in the mitochondria?

A

Fatty acid oxidation
Acetyl-CoA production
TCA cycle
Oxidative phosphorylation

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5
Q

What metabolism happens in the cytosol?

A 
Glycolysis
Fatty acid synthesis
HMP shunt
Protein synthesis
Steroid synthesis
Cholesterol synthesis
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6
Q

What processes take place in both the mito and the cytosol?

A

HUG
Heme synthesis
Urea cycle
Gluconeogenesis

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7
Q

What is the rate determining enzyme of glycolysis?

A

Phosphofructokinase

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8
Q

What enzyme commits glucose to glycolysis?

A

Hexokinase/glucokinase

Adds and phosphate group using ATP

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9
Q

What is the rate determining enzyme in gluconeogenesis?

A

Fructose 1,6 - bisphosphatase

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10
Q

What is the rate determining enzyme of the TCA cycle?

A

Isocitrate dehydrogenase

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11
Q

What is the rate determining enzyme of glycogen synthesis?

A

Glycogen synthase

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12
Q

What is the rate determining enzyme of glycogenolysis?

A

Glycogen phosphorylase

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13
Q

What is the rate determining enzyme of HMP shunt?

A

G6PD

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14
Q

What is the rate determining enzyme of de novo pyrimidine synthesis?

A

Carbamoyl phosphate synthetase II

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15
Q

What is the rate determining enzyme of de novo purine synthesis

A

Glutamine-PRPP amidotransferase

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16
Q

What is the rate determining enzyme of the urea cycle?

A

Carbamoyl phosphate synthetase I

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17
Q

What is the rate determining enzyme of fatty acid synthesis?

A

Acetyl CoA carboxylase

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18
Q

What is the rate determining enzyme of fatty acid oxidation?

A

Carnitine acyltransferase I

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19
Q

What is the rate determining enzyme of kerogenesis?

A

HMG-CoA synthase

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20
Q

What is the rate determining enzyme of cholesterol synthesis?

A

HMG-CoA reductase

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21
Q

How many molecules of ATP are made by aerobic metabolism of glucose?

A

32 via malate-aspartate shuttle

30 via glycerol-3-phosphate shuttle

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22
Q

How many molecules of ATP are made by anaerobic glycolysis?

A

2 ATP per glucose molecule

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23
Q

What type of reactions is NAD used in?

A

Catabolic process

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24
Q

What kind of reactions is NADPH used in?

A

Anabolic processes such as steroid and fatty acid synthesis
Also: respiratory burst
P-450
Glutathione reductase

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25
Q

What is the difference between hexokinase and glucokinase?

A

Hexokinase is ubiquitous with high affinity and low capacity.
It is not induced by insulin
Glucokinase is seen in only the liver and beta cells of the pancreas. It has low affinity and high capacity. It can be induced by insulin.

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26
Q

What inhibits hexokinase?

A

Glucose-6-phosphate

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27
Q

What inhibits glucokinase?

A

Fructose-6-phosphate
ATP
Citrate

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28
Q

What stimulates phosphofructokinase-1?

A

AMP

Fructose 2,6 bisphospate

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29
Q

What inhibits phosphofructokinase 1?

A

ATP

Citrate

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30
Q

Which steps in glycolysis require ATP?

A

The commitment step (glucose –> glucose-6-phosphate by glucokinase/hexokinase)
The rate limiting step (G6P –> fructose 6 phosphate by phosphofructokinase)

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31
Q

Which steps in glycolysis make ATP?

A

Steps 7 and 10
1,3 bisphosphoglycerate to 3-phosphoglycerate. By phosphoglycerate kinase
Phosphoenol pyruvate to pyruvate via pyruvate kinase

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32
Q

Which 2 enzymes are involved in the production of ATP in glycolysis?

A

Phosphoglycerate kinase

Pyruvate kinase

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33
Q

What stimulates phosphoglycerate kinase and pyruvate kinase?

A

Fructose 1,6 bisphosphate

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34
Q

Which enzymes regulate fructose 2,6 bisphosphate?

A

Fructose bisphosphatase 2

Phosphofructokinase 2

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35
Q

Which enzyme is active during the fed state?

A

Phosphofructokinase 2

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36
Q

What does PFK-2 do?

A

Activates PFK-1 to convert F6P to F1,6BP

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37
Q

What does fructose bisphosphatase 2 do?

A

Activates fructose 1,6 bisphosphatase to convert fructose 6 phosphate to glucose 6 phosphate

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38
Q

What are the levels of glucagon, insulin, cAMP, protein kinase A and the PFK-2 and FBPase-2 during the fed state?

A 
High insulin
Low glucagon
Low cAMP
Low protein kinase A
Low FbPase2
High PFK2
Net result = increased glycolysis
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39
Q

What are the levels of glucagon, insulin, cAMP, protein kinase A and the PFK-2 and FBPase-2 during the fasting state?

A 
Low insulin
High glucagon
High cAMP
High protein kinase A
Low PFK2
High FBPase-2
Net result: decreased glycolysis
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40
Q

What are the signs of arsenic poisoning?

A

Vomiting
Rice water stool
Garlic breath

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41
Q

What does arsenic inhibit?

A

Lipoid acid

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42
Q

What is the product pyruvate dehydrogenase complex reaction?

A

Pyruvate + NAD + CoA –> acetyl-CoA + NADH + CO2

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43
Q

What cofactors are involved in the pyruvate dehydrogenase complex?

A 
Pyrophosphate - B1
FAD - B2
NAD - B3
CoA - B5
Lipoid acid
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44
Q

What is PDC deficiency caused by?

A

X-linked mutation in gene for E1-alpha subunit

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45
Q

What does PDC deficiency result in?

A

Backup of substrate: pyruvate and alanine

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46
Q

What are the findings of PDC deficiency?

A

Neuro deficits starting in infancy

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47
Q

What is the treatment for PDC deficiency?

A

Increase intake of ketone is nutrients : fat and lysine/leucine

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48
Q

What is the function of PDC?

A

To transition from glycolysis to the TCA

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49
Q

What are the 4 products pyruvate can be converted to?

A

Alanine
Acetyl-CoA
Oxaloacetate
Lactate

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50
Q

What enzyme converts pyruvate to alanine?

A

Alanine amidotransferase with the help of B6

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51
Q

What enzyme converts pyruvate to lactate?

A

Lactate dehydrogenase

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52
Q

What is lactate used in?

A

Anaerobic glycolysis and the cori cycle

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53
Q

What enzyme converts pyruvate to oxaloacetate?

A

Pyruvate carboxylase (b7) with CO2 and ATP

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54
Q

What can oxaloacetate be used in?

A

TCA or gluconeogenesis

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55
Q

What enzyme converts pyruvate to acetyl-CoA?

A

Pyruvate dehydrogenase with B1,2,3,5

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56
Q

Which organs use anaerobic glycolysis?

A

RBCs, WBCs, kidney medulla, lens, cornea, testes

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57
Q

What are the products of the TCA cycle?

A

3 NADH, 1FADH2, 2 CO2, 1 GTP per acetyl CoA = 10 ATP

And we get 2 acetyl CoA molecules per 1 glucose so multiply everything by 2

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58
Q

What is the starting and end product of the TCA cycle?

A

Citrate Is Krebs’ Starting Substrate For Making Oxaloacetate:
Citrate –> Isocitrate –> alpha-Ketoglutarate –> Succinyl-CoA –> Succinate–> Fumarate–> Malate –> oxaloacetate

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59
Q

What are the irreversible reactions in the TCA cycle?

A

Acetyl CoA –> citrate by citrate synthase
Isocitrate to alpha Ketoglutarate by Isocitrate dehydrogenase (rate limiting step, produces NADH2)
Alpha Ketoglutarate to succinyl CoA by alphaketoglutarate dehydrogenase (makes NADH2)

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60
Q

Which steps produce NADH2?

A

Isocitrate to alpha-Ketoglutarate
Alpha-Ketoglutarate to Succinyl CoA
Malate to oxaloacetate

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61
Q

Which step produces FADH2?

A

Succinate to Fumarate

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62
Q

Which step uses substrate level phosphorylation to generate GTP?

A

Succinyl CoA to Succinate

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63
Q

What is complex I?

A

NADH dehydrogenase

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64
Q

What is an inhibitor of complex I?

A

Rotenone

Amytal

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65
Q

What is the consequence of electron transport inhibitors?

A

They decrease the proton gradient and block ATP synthesis

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66
Q

What is complex II?

A

Succinate dehydrogenase

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67
Q

What is complex III?

A

Cytochrome b-c

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68
Q

What is an inhibitor of complex III?

A

Antimycin A

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69
Q

What is complex IV?

A

Cytochrome c oxidase

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70
Q

What inhibits complex IV?

A

Cyanide

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71
Q

What is complex V?

A

ATP synthase = f0/f1
F0= integral membrane protein with delta stalk attached to F1
F1= made of alpha/beta subunits - converts ADP to ATP

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72
Q

What inhibits complex V?

A

Oligomycin

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73
Q

What do complex 3 and 4 do

A

Pump hydrogen ions from the matrix to the inter membrane space creating a negative charge inside the matrix and thus a larger proton gradient

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74
Q

What is oligomycin?

A

It is an ATP synthase inhibitor

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75
Q

What is the MOA of oligomycin?

A

Increases the proton gradient and stops ATP synthesis

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76
Q

Which complex uses CoQ?

A

Complex III

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77
Q

What is the effect of 2,4 dinitrophenol, aspirin, and thermogenin on the ETC?

A

Uncouple the ETC –> increase membrane permeability causing a decrease in the proton gradient stopping ATP, but continuing electron transport –> produces heat!

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78
Q

What are the irreversible enzymes in gluconeogenesis?

A

Pathway Produces Fresh Glucose:
Pyruvate carboxylase = pyruvate to oxaloacetate
Phosphoenol carboxykinase = oxaloacetate to PEP
Fructose 1,6 bisphosphatase = F1,6BP to F6P
Glucose-6-phosphatase = G6P to glucose

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79
Q

What does the G6Pase reaction need in gluconeogenesis?

A

GTP

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80
Q

What does the pyruvate carboxylase reaction in gluconeogenesis need?

A

Acetyl-CoA, biotin, ATP

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81
Q

What is the function of the HMP shunt pathway?

A

To provide a source of NADPH from glucose 6 phosphate

Provide ribose for nucleotide synthesis and glycolysis intermediates

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82
Q

Where does the HMP shunt occur?

A

In the cytoplasm

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83
Q

Does the HMP shunt require ATP?

A

No

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84
Q

At what sites does the HMP shunt occur?

A

Lactating mammary glands
Liver
Adrenal cortex
RBCs

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85
Q

What is the irreversible phase of the HMP shunt?

A

Oxidative

G6p –> 2 NADPH, CO2, ribulose-5-p by G6PD (rate limiting)

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86
Q

What is the reversible phase of the HMP shunt?

A

Nonoxidative

Ribulose-5-P –> ribose-5-p, G3P, F6P by phophopentose isomerase with B1

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87
Q

What is respiratory burst?

A

The production of reactive oxygen species for the killing of bacteria by immune cells

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88
Q

What is the end product of respiratory burst?

A

Bleach = HOCL

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89
Q

What is the first step in respiratory burst?

A

Oxidation of oxygen to a superoxide radical using NADPH

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90
Q

What is the mech of superoxide dismutase?

A

Converts superoxide radical to H2O2

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91
Q

What does myeloperoxidase do?

A

Converts H2O2 to bleach

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92
Q

What does bacterial catalase do?

A

Converts H2O2 to water and oxygen so that it cannot be used by the host to make ROIs

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93
Q

What does G6PD do in respiratory burst?

A

Generates more NADPH for respiratory burst using G6P

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94
Q

How do we deal with our H2O2?

A

Reduce it using glutathione

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95
Q

What replenishes/reduces glutathione?

A

NADPH

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96
Q

What is the inheritance pattern of G6PD deficiency?

A

X linked recessive

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97
Q

What is the clinical presentation of G6PD deficiency?

A

Back pain then hematuria after infection, antibiotics, fava beans.

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98
Q

What do you see in the peripheral blood smear in G6PD deficiency?

A

Heinz bodies

Bite cells

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99
Q

What is the problem in G6PD deficiency?

A

Can’t reduce NADP to NADPH and therefore you can’t reduce glutathione so cells are susceptible to oxidative damage

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100
Q

What is the inheritance pattern of essential fructosuria?

A

Auto recessive

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101
Q

What is the defect in essential fructosuria?

A

Defect in fructokinase

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102
Q

What are the findings of essential fructosuria?

A

Fructose in blood and urine

Otherwise asx

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103
Q

What is the inheritance pattern of fructose intolerance?

A

Auto recessive

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104
Q

What is the defect in fructose intolerance?

A

Defect in aldolase B that results in the accumulation of fructose-1-phosphate thereby depleting the phosphate pool. Causes inhibition of glycogenolysis and gluconeogenesis

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105
Q

What are the sx of fructose intolerance?

A

Hypoglycemia
Jaundice
Cirrhosis
Vom

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106
Q

What is the treatment of fructose intolerance?

A

Decrease intake of fructose and sucrose

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107
Q

What is the inheritance pattern of galactokinase deficiency?

A

Auto recessive

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108
Q

What are the signs of galactokinase deficiency?

A

Infantile cataracts
Lack of tracking objects
Lack of development of social smile
Galactose in the blood

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109
Q

What is the defect in classic galactosemia?

A

Absence of galactose-1-phosphate uridyltransferase that causes toxic buildup of galacitol

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110
Q

What is the inheritance pattern of classic galactosemia?

A

Auto recessive

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111
Q

What are the findings of classical galactosemia?

A

Infantile cataracts, mental retardation, failure to thrive, jaundice, hepatomegaly

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112
Q

What is the treatment for classic galactosemia?

A

Exclude galactose and lactose from the diet

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113
Q

Where does galactitol deposit in the body?

A

Lens of the eye

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114
Q

What does aldose reductase do?

A

Converts glucose to its alcohol form, sorbitol

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115
Q

What does sorbitol dehydrogenase do?

A

Converts sorbitol to fructose

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116
Q

What is the consequence of an sorbitol dehydrogenase deficiency?

A

Sorbitol accumulates in the cells and sets up a gradient for water to come in –> osmotic damage = cataracts, retinopathy, peripheral neuropathy

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117
Q

Which organs are most susceptible to sorbitol accumulation and why?

A

Schwann cells, kidneys, eyes because they only have aldose reductase - no sorbitol dehydrogenase

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118
Q

What is the problem in lactase deficiency?

A

Loss of a brush border enzyme

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119
Q

What are the sx?

A

Bloating, cramps, osmotic diarrhea

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120
Q

Who is more likely to have lactase deficiency?

A

Asians and blacks

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121
Q

What are the essential amino acids?

A

Met, Val, His, Ile, Phe, Thr, Trp, Leu, Lys

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122
Q

What are the essential glucogenic amino acids?

A

Met, Val, His

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123
Q

What are the essential glucogenic/ketogenic amino acids?

A

Ile, Phe, Thr, Trp

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124
Q

What are the essential ketogenic amino acids?

A

Leu, Lys

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125
Q

What are the acidic amino acids?

A

Asp
Glu
These are negatively charged and bodily pH

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126
Q

What are the basic amino acids?

A

Arg, Lys, His

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127
Q

What is the most basic protein?

A

Arg

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128
Q

Which amino acid has no charge at bodily ph?

A

His

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129
Q

What is the urea cycle?

A

Ordinarily Careless Crappers Are Also Frivolous About Urination.
Ornithine + Carbamoylase to Citrulline via ornithine transcarbamoylase
Then Aspartate plus ATP with Citrulline converted to argininosuccinate via argininosuccinate synthetase
Argininosuccinate - Fumarate = Arginine
Arginine + water = urea via arginase

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130
Q

Where does the urea cycle occur?

A

In the liver

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131
Q

What does the Cori cycle do?

A

Uses lactate from anaerobic glycolysis for gluconeogenesis

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132
Q

What is the glucose-alanine cycle?

A

Used as a secondary transport of ammonium from muscles

Used for gluconeogenesis during starvation

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133
Q

What other amino acid is used for transport of ammonium in the body?

A

Glutamate/alpha ketoglutarate

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134
Q

What is the rate limiting step in the urea cycle?

A

The first step using CO2, NH4, and 2 ATP to make carb amigo phosphate

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135
Q

What is the problem in hyperammonemia?

A

Excess NH4 results in depletion of alpha-ketoglutarate and therefore inhibits the TCA cycle so ATP production is impaired

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136
Q

What is the tx for hyperammonemia?

A

Limit protein in diet
Benzoate or phenylbutyrate - bind amino acid and lead to excretion
Lactulose to acidify the GI tract and trap NH4 for excretion

137
Q

What are the sx of ammonia intoxication?

A 
Asterixis
Slurring of speech
Somnolence
Vomiting
Cerebral edema
Blurring of vision
138
Q

What is the most common urea cycle disorder?

A

Ornithine transcarbamoylase deficiency

139
Q

What is the inheritance pattern of ornithine transcarbamoylase deficiency?

A

X linked recessive

140
Q

What is the problem in ornithine transcarbamoylase deficiency?

A

The body can’t eliminate ammonia

141
Q

What are the findings in ornithine transcarbamoylase deficiency?

A

Increased orotic acid in the urine and blood
Decreased BUN
Sx of hyperammonemia: asterixis, somnolence, vom, slurred speech, cerebral edema, blurred vision

142
Q

What amino acid is epinephrine derived from?

A

Phenylalanine

143
Q

What amino acid is norepinephrine derived from?

A

Phenylalanine

144
Q

What amino acid is dopamine derived from?

A

Phenylalanine

145
Q

What amino acid is melanin derived from?

A

DOPA from phenylalanine

146
Q

What amino acid is thyroxine derived from?

A

Tyrosine from phenylalanine

147
Q

What amino acid is melatonin derived from?

A

Serotonin from tryptophan

148
Q

What amino acid is serotonin derived from?

A

Tryptophan

149
Q

What amino acid is niacin derived from?

A

Tryptophan

150
Q

What amino acid is histamine derived from?

151
Q

What amino acid is porphyrin derived from?

152
Q

What vitamin is needed for the synthesis of porphyrin?

153
Q

What amino acid is creatinine derived from?

154
Q

What amino acid is urea derived from?

155
Q

What amino acid is nitric oxide derived from?

156
Q

What amino acid is GABA derived from?

157
Q

What amino acid is glutathione derived from?

158
Q

Which vitamins are need for the synthesis of norepinephrine?

A

B6 and vit C

159
Q

Which enzyme is responsible for converting dopamine to norepinephrine?

A

Dopamine B-hydroxylase

160
Q

Which enzyme is responsible for converting norepinephrine to epi?

A

Phenylethanolamine N-methyltransferase

161
Q

What does dopamine get broken down to by MAO and COMT?

A

HVA- homovanyllic acid

162
Q

What does norepinephrine get broken down into via MAO or COMT?

163
Q

What does epinephrine get broken down into by MAO or COMT?

A

Metanephrine

164
Q

What is the inheritance pattern of phenylketonuria?

A

Auto recessive

165
Q

What is the problem in phenylketonuria?

A

Due to a deficiency in phenylalanine hydroxylase or decreased tetrahydrobiopterin cofactor so tyrosine becomes essential and phenylalanine ketones spill over into the urine

166
Q

What are the phenylketones?

A

Phenyl-acetate
Phenyl lactate
Phenylpyruvate

167
Q

What are the sx of phenylketonuria?

A 
Mental retardation
Musty body odor
Fair skin
Seizures
Eczema
Growth retardation
168
Q

What is the tx for phenylketonuria?

A

Decreased phenylalanine

Increased tyrosine intake

169
Q

What is maternal PKU?

A

Lack of proper dietary therapy during pregnancy

170
Q

What does maternal PKU cause in the infant?

A

Microcephaly
Mental retardation
Growth retardation
Congenital heart defects

171
Q

What is alkaptonuria?

A

A congenital deficiency in homogentistic acid oxidase in the degradation pathway of tyrosine to fumarate

172
Q

What is the inheritance pattern of alkaptonuria?

A

Auto recessive

173
Q

What are the findings of alkaptonuria?

A

Dark connective tissue
Brown pigmented sclera
Urine that turns black with exposure to air
Debilitating arthralgias

174
Q

What is the inheritance pattern of albinism?

A

Variable due to locus heterozygosity
Auto recessive (deficient tyrosinase)
X liked recessive (ocular)

175
Q

What is the deficiency in albinism?

A

Tyrosinase - cant synthesize melanin from tyrosine
Tyrosine transporters
Can result from lack of migration of neural crest cells

176
Q

What are albinos at increased risk for?

177
Q

What is the inheritance pattern of homocystinuria?

A

Auto recessive

178
Q

What are the 3 forms of homocystinuria?

A

Cystathionine synthase deficiency
Cystathionine synthase has decreased affinity for pyridoxal phosphate
Homocysteine methyltransferase deficiency

179
Q

What are the findings in homocystinuria?

A 
Homocysteine in the urine
Mental retardation
Osteoporosis
Tall statur
Kyphosis
Lens subluxation (down and in)
Atherosclerosis
180
Q

What is the tx for decreased affinity of cystathionine synthase for pyridoxal phosphate?

A

Increased B6 in the diet

181
Q

What is the treatment for cystathionine synthase deficiency?

A

Decreased Met and increase cysteine, B12 and folate in the diet

182
Q

What is cystinuria?

A

Hereditary defect of renal tubular amino acid transporter for cysteine, ornithine, lysine, and arginine in the PCT of the kidneys

183
Q

What is the inheritance pattern of cystinuria?

A

Auto recessive

184
Q

What is the treatment of cystinuria?

A

Hydration

Alkalinization of the urine

185
Q

What is cystine?

A

2 cysteines connected with a disulfide bond

186
Q

What is seen in cystinuria?

A

Precipitation of hexagonal crystals

Renal stag horn calculi

187
Q

What is the defect in maple syrup urine disease?

A

Blocked degradation of branched amino acids (Ile, leu, Val ) due to decreased alpha-ketoacid dehydrogenase (B1)

188
Q

What is the inheritance pattern of maple syrup urine disease?

A

Auto recessive

189
Q

What are the sx of maple syrup urine disease?

A

Severe CNS defects
Mental retardation
Death

190
Q

What is the effect of maple syrup urine disease?

A

Increased alpha-ketoacid in the blood, especially leu

191
Q

What is the inheritance pattern of Hartnup disease?

A

Auto recessive

192
Q

What is the defect in Hartnup disease?

A

Defective neutral amino acid transporter on renal and intestinal epi cells that causes increased Trp excretion and decreased absorption from the GI.

193
Q

What does Hartnup disease cause?

A

Pellagra - dermatitis, dementia, diarrhea, death

194
Q

What else causes pellagra?

A

B3 deficiency

195
Q

What is the structure of glycogen?

A

Branches have alpha (1,6) bonds

Linkages have alpha (1,4) bonds

196
Q

What happens to glycogen during glycogenolysis?

A

It is broken down to be used in glycolysis

Glycogen –> glucose 1 phosphate –> glucose 6 phosphate –> glycolysis

197
Q

Where is glycogen stored?

A

In the liver

198
Q

What activates glycogen phosphorylase kinase?

A

Protein kinase A/calcium/calmodulin in muscle

199
Q

What happens when insulin is high?

A

Receptor tyrosine kinase dimerizes and activates protein phosphatase which inactive glycogen phosphorylase kinase

200
Q

What is the enzyme that converts glucose-1-phosphate to UDP-glucose?

A

UDP-glucose pyrophosphorylase

201
Q

What converts UDP-glucose into glycogen?

A

Glycogen synthase

202
Q

What enzyme converts glycogen back into glucose-1-phosphate?

A

Glycogen phosphorylase

203
Q

What is the missing enzyme in Von Gierke’s disease?

A

Glucose-6-phosphatase

204
Q

What are the findings in Von Gierke’s disease?

A

Sever fasting hypoglycemia
Increased glycogen in the liver
Increased lactic acid in the blood
Hepatomegaly

205
Q

What is the deficient enzyme in Pompe’s disease?

A

Alpha-1,4-glucosidase

206
Q

What are the findings in Pompe’s disease?

A

Cardiomegaly
Systemic findings leading to an early death
Pompe’s trashes the pump: heart, liver, muscles

207
Q

What is the deficient enzyme in Cori’s disease?

A

De branching enzyme: alpha-1,6-glucosidase

208
Q

What are the findings of Cori’s disease?

A

Milder sx of type I (Von Gierke’s) with normal levels of blood lactate

209
Q

What is the deficient enzyme in McArdle’s?

A

Skeletal muscle glycogen phosphorylase

210
Q

What are the findings in McArdle’s?

A

Increased glycogen in muscle
Myoglobinuria aft exercise
Muscle cramps

211
Q

What are the 4 glycogen storage diseases we have to know?

A 
Very Poor Carbohydrate Metabolism
Von Gierke's - type I
Pompe's -type II
Cori's -type III
McArdle's - type V
212
Q

What are the inheritance patterns of these 4 glycogen storage diseases?

A

Auto-recessive

213
Q

What is the deficient enzyme in Fabry’s disease?

A

Alpha-galactosidase A

214
Q

What is the accumulated substrate in Fabry’s disease?

A

Ceramics trihexoside

215
Q

What is the inheritance pattern of Fabry’s?

A

X linked recessive

216
Q

What are the findings of Fabry’s?

A

Peripheral neuropathy of the hands/feet
Angiokeratomas
CV/renal disease

217
Q

What is the most common lysosomal storage disease?

A

Gaucher’s – auto recessive

218
Q

What is the deficient enzyme in Gaucher’s?

A

Glucocerebrosidase

219
Q

What is the accumulated substrate in Gaucher’s?

A

Glucocerebroside

220
Q

What are the findings in Gaucher’s?

A

HSM
Aseptic necrosis of the femur
Bone crises
Gaucher’s cells = macs that look like crumpled tissue pap

221
Q

What is the deficient enzyme in Niemann-Pick disease?

A

Sphngimyelinase

222
Q

What is the accumulated substrate in Niemann-Pick’s?

A

Sphingomyelin

223
Q

What are the findings in Niemann-Pick’s?

A

Progressive neurodegeneration
HSM
Cherry-red spot in macula
Foam cells

224
Q

What is the deficient enzyme in Tay-Sachs disease?

A

Hexosaminidase A

225
Q

What is the accumulated substrate in Tay Sachs?

A

GM2 ganglioside

226
Q

What are the findings in Tay Sachs?

A

Progressive neurodegeneration
Developmental delay
Cherry red spot on macula
Lysosomes with onion skin

227
Q

What is the deficient enzyme in Krabbe’s disease?

A

Galactocerebrosidase

228
Q

What is the accumulated substrate in Krabbe’s?

A

Galactocerebroside

229
Q

What are the findings in Krabbe’s disease?

A

Peripheral neuropathy
Developmental delay
Optic atrophy
Globoid cells

230
Q

What is the defient enzyme in Metachromatic leukodystrophy?

A

Arylsulfatase A

231
Q

What is the accumulated substrate in Metachromatic leukodystrophy ?

A

Cerebroside sulfate

232
Q

What are the findings of Metachromatic leukodystrophy?

A

Central and peripheral demyelination
Ataxia
Dementia

233
Q

What is the deficient enzyme in Hurler’s syndrome?

A

Alpha-l-iduronidase

234
Q

What are the accumulated products in Hurler’s syndrome?

A

Heparan sulfate, dermatan sulfate

235
Q

What are the findings in Hurler’s syndrome?

A 
Developmental delay
Gargoylism
Airway obstruction 
Corneal clouding
HSM
236
Q

What is the deficient enzyme in Hunter’s syndrome?

A

Iduronate sulfatase

237
Q

What are the accumulated products in Hunter’s syndrome?

A

Heparan sulfate

Dermatan sulfate

238
Q

What are the findings in Hunter’s syndrome?

A

Mild Hurler’s
Aggressive behavior
No corneal clouding

239
Q

Which lysosomal storage disease are X linked?

A

Fabry’s and Hunter’s

240
Q

What is the inheritance pattern of the other lysosomal storage diseases?

A

Auto recessive

241
Q

What is carnitine deficiency?

A

Inability to transport LCFAs into mitochondria –> toxic buildup

242
Q

What are the sx of carnitine deficiency?

A

Weakness
Hypotonia
Hypoketotic hypoglycemia

243
Q

Where does FA degradation occur?

A

In the mitochondrial matrix

244
Q

Where does FA synthesis happen?

A

In the cytoplasm

245
Q

What is the main regulation on beta oxidation of FAs?

A

Malonyl-CoA inhibits carnitine acyl transferase

246
Q

What is the result of FA degradation?

A

Acetyl-CoA groups for TCA cycle or ketone body production

247
Q

Which vitamin is used during fatty acid synthesis?

A

B7 -biotin to carboxylate acetyl-CoA to become malonyl-CoA

248
Q

Why do we make ketone bodies?

A

Because oxaloacetate becomes depleted during long periods of starvation or after alcohol so TCA cycle is stalled and glucose and FAs are shunted toward making ketone bodies

249
Q

What are the ketone bodies made?

A

Acetoacetate

B-hydroxybutyrate

250
Q

What is the rate limiting enzyme for ketone body production?

A

HMG CoA synthase

251
Q

What is used for energy during the first seconds of exercise?

A

Stored ATP and creating phosphate

252
Q

What kind of metabolism is going on during prolonged exercise?

A

Aerobic metabolism and FA oxidation

253
Q

How much energy does 1 gram of protein provide?

254
Q

How much energy does 1 gram of Fat provide?

255
Q

How long do glycogen reserves last?

256
Q

What are the major mechanisms that maintain blood glucose levels during days 1-3 of starvation?

A

Hepatic glycogenolysis
Muscle and liver use FAs
Hepatic gluconeogenesis from lactate and alanine, FAs and TAGs

257
Q

What is the major source of energy after 3 days of starvation?

A

Ketone bodies

258
Q

What is the source of energy after ketone body production is depleted?

A

Vital proteins –> organ failure, death

259
Q

What are ketone bodies made out of?

A

Acetyl-CoA –> HMG CoA

260
Q

What is chokes too made out of?

261
Q

What enzyme esterifies 2/3 of plasma cholesterol?

A

Lecithin-cholesterol acyl transferase (makes HDL)

262
Q

What does pancreatic lipase do?

A

Degrades dietary TGs in small intestine

263
Q

What do lipoprotein lipase do?

A

Degrades TGs circulating in chylomicrons and VLDL

264
Q

What does hepatic TG lipase do?

A

Degrades TG remaining in IDL

265
Q

What does hormone-sensitive lipase do

A

Degrades TGs stored in adipocytes

266
Q

What does cholesterol ester transfer protein do

A

Mediates transfer of cholesterol esters to lipoprotein particles (VLDL, IDL, LDL)

267
Q

What does apolipoprotein E do?

A

Mediates remnant uptake in all transporters except LDL

268
Q

What does apolipoprotein A-I do?

A

Activates LCAT

269
Q

What does apolipoprotein C-II do

A

Lipoprotein lipase cofactor

Helps degrade from HDL, VLDL, chylomicrons

270
Q

What does apolipoprotein B48 do?

A

Mediates chylomicron secretion

271
Q

What does apolipoprotein B100 do?

A

Binds LDL receptor

272
Q

What does LDL do?

A

Delivers cholesterol from liver to tissues.

273
Q

How is LDL taken up by target cells?

A

Via receptor mediated endocytosis

274
Q

How is LDL formed?

A

By hepatic lipase modification of IDL in peripheral tissue

275
Q

What do chylomicrons do?

A

Deliver dietary TGs to peripheral tissue

Delivers cholesterol to liver

276
Q

What are chylomicrons secreted by?

A

Intestinal epithelial cells

277
Q

What does VLDL do?

A

Delivers hepatic TGs to peripheral tissue

Secreted by the liver

278
Q

How is IDL formed?

A

During degradation of VLDL

279
Q

What does IDL do?

A

Delivers triglycerides and cholesterol to liver

280
Q

What does HDL do?

A

Delivers cholesterol from periphery to liver

Acts as a repository for apoC and apoE

281
Q

Where is HDL secreted from?

A

Liver and intestines

282
Q

What is the inheritance pattn of I-hyperchylomicronemia?

A

Auto recessive

283
Q

What is the defect in I-hyperchylomicronemia?

A

Deficient LPL or apoC-II causes pancreatitis, HSM, eruptive/pruritic xanthomas

284
Q

What is elevated in the blood in I-hyperchylomicronemia?

A

Chylomicrons, TGs, cholesterol

285
Q

What is the inheritance pattern of IIa-familial hypercholesterolemia?

A

Auto dominant

286
Q

What is the problem in IIa- familial hypercholesterolemia?

A

Absent or decreased LDL receptors that causes accelerated atherosclerosis, tendon (Achilles) xanthomas, corneal areus

287
Q

What is elevated in the blood in IIa-familial hypcholesterolemia?

A

LDL, cholesterol

288
Q

What is the inheritance pattern of IV-hypertriglyceridemia?

289
Q

What is the problem in IV-hypertriglyceridemia?

A

Hepatic overproduction of VLDL that causes pancreatitis

290
Q

What is elevated in the blood in IV-hypertriglyceridemia?

291
Q

What is the inheritance pattern of abetalipoproteinemia?

A

Auto recessive

292
Q

What is the mutation in abetalipoproteinemia?

A

Mutation in microsomal transfer protein gene so you have decreased levels of apoB48 and B100 so there is decreased chylomicron and VLDL synthesis and secretion

293
Q

What are the findings of abetalipoproteinemia?

A 
Failure to thrive
Steatorrhea
Acanthocytosis
Ataxia
Night blindness
294
Q

What do you see on bx of intestines?

A

Lipid accumulation within enterocytes due to inability to export lipid as chylomicron

295
Q

What enzyme converts phenylalanine to tyrosine?

A

Phenylalanine hydroxylase + BH4 cofactor

296
Q

What enzyme reduces BH2 to BH4?

A

Dihydropteridine reductase (using NADP–>NADPH)

297
Q

What is BH4 used in?

A

The synthesis of tyrosine, DOPA, serotonin and nitric oxide

298
Q

What enzyme converts tyrosine to DOPA?

A

Tyrosine hydroxylase + BH4

299
Q

What enzyme converts DOPA to dopamine?

A

DOPA decarboxylase + B6

300
Q

What enzyme converts dopamine to norepinephrine?

A

Dopamine b-hydroxylase + Vit C

301
Q

What enzyme converts norepinephrine to epi?

A

Phenylethanolamine n-methyltransferase + SAM

302
Q

What is SAM?

A

ATP+methionine

303
Q

What is SAM used for?

A

Transferring methyl groups

304
Q

What drug inhibits dopa decarboxylase?

305
Q

What stimulates phenylethanolamine n-methyltransferase?

306
Q

What is malignant/atypical PKU?

A

Deficiency in dihydropteridine reductase - no BH4
Decreased tyrosine, dopa, serotonin, nitric oxide.
May see hyperprolactinemia

307
Q

What does fructose-2,6-bis phosphatase do?

A

Converts fructose-2,6-phosphate to fructose-6-phosphate

308
Q

What does fructose-2,6-bisphosphate stimulate?

A

Phosphofructokinase 1(glycolysis)

309
Q

When is fructose-2,6-bisphosphate active?

A

In the fasting state

310
Q

What does phosphofructokinase 2 do?

A

Converts fructose-6-phosphate to fructose-2,6-phosphate

311
Q

What does aldose reductase do in the galactose pathway?

A

Converts galactose to galactitol

312
Q

When is aldose reductase active in the galactose pathway?

A

In classic galactosemia and galactokinase deficiency

313
Q

What does galactose-1-phosphate uridyltransferase do?

A

Converts galactose-1-phosphate to glucose-1-phosphate with the help of 4-epimerase and UDP-glucose

314
Q

What does galactokinase use in its reaction?

315
Q

What enzyme converts H2O2 to two molecules of water

A

Glutathione peroxidase

316
Q

What does fructokinase do?

A

Converts fructose to fructose-1-p

317
Q

What does aldolase B do?

A

Converts fructose-1-p to dihydroxyacetone-P and aglyceraldehyde

318
Q

What does triose kinase do?

A

Converts glyceraldehyde to glyceraldehyde-3-p

319
Q

How does glyceraldehyde become glycerol?

A

By oxidizing NADH to NAD

320
Q

Which enzymes are going to be affected most in alcoholics?

A

Alpha-ketoglutarate dehydrogenase
Pyruvate dehydrogenase
Transketolase
Branched chain amino acid dehydrogenase

321
Q

What are the sx of dry beri beri?

A

Polyneuritis

Symmetrical muscle wasting

322
Q

What are the sx of wet beri beri?

A

High output heart failure, edema

323
Q

What can cause pellagra?

A 
Hartnup disease
Malignant carcinoid syndrome
INH 
Corn diet
Alcoholism
324
Q

Which enzyme of the TCA cycle is most effected by B2 deficiency?

A

Succinate dehydrogenase

325
Q

What enzymes are effected by a B6 deficiency?

A

Alanine aminotransferase (pyruvate to alanine)
Delta-levulinic acid synthase (glycine + succinate)
Glutamate –> GABA
Tryptophan –> niacin
Histidine –> histamine
Dopa –> dopamine
Homocysteine to cystathionine

326
Q

What enzyme would be most affected by a biotin deficiency?

A

Pyruvate carboxylase (pyruvate to oxaloacetate)
Acetyl-CoA carboxylase (acetyl CoA to malonyl CoA)
Propionyl CoA carboxylase (propionyl CoA to methyl malonyl CoA

327
Q

Why does methyl malonyl CoA build up if there is a B12 deficiency?

A

Because b12 is a cofactor in the conversion of methyl malonyl CoA to succinyl CoA

328
Q

What does alanine aminotransferase do?

A

Transfers amino groups from alanine to alpha ketoglutarate (to become glutamate) in the muscle and liver –> urea

329
Q

What enzyme used ATP in the urea cycle?

A

Arginosuccinate synthetase

330
Q

What is the enzyme that converts homocysteine to methionine?

A

Homocysteine methyltransferase using B12

331
Q

How is cystathionine synthesized?

A

From homocysteine + serine by cystathionine synthase and B6

332
Q

What activates glycogen phosphorylase kinase?

A

Calcium/calmodulin
Activated in the fasting state when glucagon binds G protein receptor and causes signal transduction by increase in adenylyl cyclase and camp –> increase protein kinase A

333
Q

What does protein kinase A do?

A

Phosphorylation glycogen phosphorylase kinase to become active

334
Q

What does glycogen phosphorylase kinase do?

A

Phosphorylates glycogen phosphorylase to become active for glycogenolysis

335
Q

What activates protein phosphatase?

336
Q

What does protein phosphatase do?

A

Dephosphorylates glycogen phosphorylase kinase and glycogen phosphorylase to become inactive

337
Q

What enzyme converts acetoacetate to acetoacetyl CoA in ketogenesis?

A

Thiophorase

338
Q

What enzyme converts acyl CoA to acetyl CoA groups?

A

Acyl CoA dehydrogenase in fatty acid oxidation with the help of B2

339
Q

What does fatty acid CoA synthetase do?

A

Coverts fatty acids and CoA to acyl-CoA to be transported into the mito

340
Q

What does ATP citrate lyase do?

A

Converts citrate to acetyl CoA in fatty acid synthesis

341
Q

Which enzyme is decreased in a deficiency of Riboflavin?

A

Succinate dehydrogenase

Biochem First aid (3 decks)

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