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Biochem Flashcards

1
Q

Orotic aciduria

A
  • AR Deficiency in UMP synthase needed for the conversion of orotic acid to UMP (for de novo pyrimidine synthesis)
  • High orotic acid in urine, megaloblastic anemia, NO HYPERAMMONEMIA
  • OTC deficiency (acc. of carbamoyl phosphate) XLR, MC urea cycle d/o

Similar symptoms w/ hyperammonemia, no megaloblastic anemia

Tx: Oral Uridine (converted to UMP and inhibits CPS 2, decr orotic acid)

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2
Q

Adenosine Deaminase Deficiency

A
  • AR Deficiency in adenosine deaminase, enzyme needed to met/convert adenosine into inosine.
  • Acc. of ATP and dATP cause feedback inhibition of ribonucleotide reductase –> prevents DNA synthesis.

Affects labile cells (i.e. lymphocytes) AR SCID

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3
Q

Lesch- Nyhan Syndrome

A

-XLR Deficiency in HGPRT- enzyme needed for purine salvage (hypoxanthine –> IMP and guanine –> GMP).

Results in excess uric acid prod and de novo purine synth.

Symptoms: self-mutilation (lip biting), retardation, aggression, hyperuricemia, gout), dystonia, writhing

Tx: allopurinol or febuxostat

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4
Q

p53 and Cancer

A

-p53- a TF involved in activating DNA repair enzymes and apoptosis. -Regulates the cell cycle at G1 to S progression. -Regulated by mdm2 (ubiquitin ligase)/DNA dmaage

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5
Q

Rb and Cancer

A

-Rb is a tumor suppressor protein involved in inhibiting cell cycle TFs (i.e. E2F) and chromatin remodeling. -Regulates the cell cycle at G1 to S progression.

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6
Q

Xeroderma Pigmentosa

A

* Small child with multiple skin lesions (squamous cell carcinoma, melanoma, and basal cell carcinoma) and severe sensitivity to sunlight. AR inheritance * Mutation in nucleotide excision repair ; unable to repair UV-induced thymidine dimer formation.

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7
Q

Hereditary nonpolyposis colorectal cancer (HNPCC)

A

* Predisposes to CRC w/o polyp hx (proximal/left colon) and endometrial hyperplasia * Defect in nucleotide mismatch repair. AD inheritance. * Microsatellite instability

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8
Q

Ataxia Telangiectasia

A

* Triad: * Cerebellur defects (i.e. ataxia) * IgA deficiency (intestinal AB) Increased susceptibilty to leukemia and lymphoma due to chromosome instability Caused by a defect in the ATM gene that codes for double strand break repair enzyme (repairs via Non-homologus end-joining). AR inheritance

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9
Q

Osteogenesis imperfect (Type 1 collagen)

A

-Deficiency in Type 1 procollagen formation (triple helix formation) - Bone, skin, tendon, and wound repair -Multiple bone fractures, blue sclerae (translucent CT layer over choroid), hearing loss (abnormal middle ear bones), dental imperfections (lack of dentin) -Type 2 collagen OI is embrylogically lethal

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10
Q

Scurvy

A

-Deficiency in Vit C (absorbic acid); impaired hydroxylation of proline and lysine residues in collagen 1-4 needed for crosslinking and stabilization -malaise/lethargy,spongy/bloody gums, skin petichiae and brusing (thighs),

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11
Q

Ehlers-Danlos syndrome (Type 3 collagen)

A

-Deficiency in type 3 collagen (reticulin) synthesis; impaired clevage -Skin, vasculature, uterus, etc. -Hyperextensible skin and joints, easy bruising, berry aneurysms

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12
Q

Alport syndrome (Type 4 collagen)

A

-Deficiency in Type 4 collagen synthesis (XR) -Basement membrane in kidney, ears, and eyes. -Nephritis, deafness, and blindness

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13
Q

Marfan’s syndrome

A

-Deficiency in fibrillin gene- the structural component of elastin -long/slender limbs, kyphosis/scoliosis, osteoarthritis, poor eyesight and hearing

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14
Q

Chediak-Higashi syndrome?

A

-Deficiency in LYST gene; impairs MT polymerization needed for trafficking phagolysosomes to the lysosome and axoplasmic neuronal transport -recurrent bacteiral infections, albinism, peripheral neuropathy

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15
Q

Kartagener’s Syndrome

A

-Deficiency in the production of dynein- an ATPase that links peripheral MT doublets and allows for cilium sliding and cilia bending -Male and female infertility, recurrent sinusitis (failure of resp. tract outward movement) - Assoc. with situs inversus

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16
Q

GLUT transporters (5)

A

1 RBCs, blood brain barrier 2 Liver, small intestine. pancreas. High capacity, high Km (low affinity). Liver eats last. - Insulin-mediated glucose uptake 3 Neurons, placenta, testes. Low Km (high affinity) 4 Muscle, fat and heart. -Insulin-mediated glucose uptake 5 Fructose transporter

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17
Q

Insulin vs. Glucagon

A

**- Glucagon/Epi; kinase **

  • (incr cAMP –> incr PKA)
  • Glycogen phosphorylase (glycogenolysis)
  • Adipose lipase (FFA release)
  • Gluconeogenesis

- Insulin; phosphatase

  • (Tyr kinase dimeriz. –>inc. protein phosphatase)
  • Glycogen synthetase (glyconeogenesis
  • Lipid/protein catabolism
  • GLUT2 and 4 uptake
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18
Q

Hexokinase vs Glucokinase

A
  • Responsible for phosphorylating **glucose –> G6P **
  • Glucokinase is only in the liver and pancreas
  • Glucokinase has higher Km (MM constant) and high Vmax
  • Glucokinase has lower affinity for glucose
  • Glucokinase is not inhibited by G6P
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19
Q

Pyruvate dehydrogenase deficiency

A

* Nuerological defects (less ATP prod.) and lactic acidosis ( increased pyruvate) * Congenital or in alcoholics (B1 deficiency) * Tx: 2 ketogenic amino acids (won’t inc. lactic acid): Leucine and lysine

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20
Q

Pyruvate metabolsim

A
  1. Pyruvate –> alanine (ALT). For NH4+ transport following amino acid catabolism.
  2. Pyruvate –> oxaloacetate (pyruvate carboxylase). For gluconeogenesis or TCA replenishment.
  3. Pyruvate –> Lactate. For E in RBCs.
  4. Pyruvate –> Acetyl CoA (pyruvate dehydrogenase). For TCA cycle.
    - Regulated by NADH:NAD+ ratio
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21
Q

Ethanol metabolism

A
  • Met. of ethanol in liver produces NADH
  • High NADH:NAD+ ratio –> lactic acid production (NAD+ is the LR in ethanol met)
  • High lactate
  • Met. acidosis with resp. comp. (high anion gap)
  • Low glycerol-3-phos
  • Low pyruvate levels = no gluconeogenesis
  • High FA synthesis (Fatty liver)
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22
Q

Krebs cycle

A

* Citrate synthetase inhibited by ATP * Citrate: * Inhibts PFK1 (RLE of glycolysis) * Activates Acetyl CoA Carboxylase (RLE of FA synthesis)

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23
Q

Metabolic disorders

A
  • Glycolysis -Fructose met (Liver) - Galactose met (Liver) - Amino acid/Urea met - FA met - Glycogen storage disease - Lysosomal storage disease - Dyslipidemias
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24
Q

Disorders of fructose metabolism (sucrose = glucose + fructose)

A
  • **Essential fructosuria **
  • Deficiency in fructokinase (AR)
  • Asymptomatic; found in blood and urine
  • Fructose intolerance
  • Deficiency in Aldolase B (AR)
  • Hypoglycemia, jaundice, liver cirrhosis
  • Acc. of F1P–>dec. intracell Phos–> inhib.glycogenolysis/gluconeogenesis
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25
Q

Disorders of galactose metabolism (lactose = glucose +galactose)

A
  • Galactokinase deficiency (AR)
  • Galactose in blood and urine (from breast milk)
  • Infant cataracts; no object tracking or smile
  • Aldose reductase act.–> Acc. of galactitol
  • Classic Galactosemia
  • Deficiency in galactose 1 phos uridyltrans. (AR)
  • Failure to thrive, jaundice, infant cataracts
  • Aldose reductase act.–> Acc. of galactitol
  • Acc. of F1P–>dec. intracell Phos–> inhib.glycogenolysis/gluconeogenesis
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26
Q

Aldose reductase

A
  • Glucose –> sorbitol–> fructose
  • Alt. method of trapping glucose ( hyperglycemia )
  • Lens and neurons = no sorbitol dehydr. enzyme
  • Sorbitol acc. –> osmotic damage (i.e cataracts, retinopathy, and nueropathy)
  • Galactose –> galactitol
  • Galactitol acc. –> osmotic damage (i.e cataracts)
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27
Q

Essential amino acids (glucogenic aa vs. ketogenic aa)

A

Glucogenic: converted into pyruvate or TCA intermediates

  • Methionine, Valine, Histidine+
  • Arg and His only essential during devel

Ketogenic: converted into acetyl CoA –> ketone bodies (acetoacetic acid and B-hydroxybutyric)

-Leucine and Lycine+

Both: Ile, Phe, Thr, Trp

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28
Q

Amino acid catabolism (fasting state; aspartate)

Allows muscle to use AAs as energy

A
  1. Muscle protein breakdown.
  2. Muscle transamination:
    - Aspartate + a-KG–>OAA+Glutamate (AST)
    - Glutamate + Pyruvate–> a-KG + Alanine (ALT)

Alanine transported in blood to liver

  1. Liver transamination:
    - Alanine + a-KG –> Pyruvate + Glutamate (ALT)
    - Pyruvate –> Glucose (Gluconeogensis)
    - Glutamate –> NH4+ (Glutamate dehydrogenase)
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29
Q

Amino acid catabolism (fasting state; glutamate)

A
  1. Muscle protein breakdown. 2. Peripheral issue transamination: -Glucogenic aa+a-KG–>Oxaloacetate+ Glutamate (exits) -Glutamate + NH4+ –> Glutamine (Glutamine syn) 3. Liver transamination: -Glutamine –> Glutamate + NH4 (Glutaminase) - Glutamate –> NH4+ (Glutamate dehydrogenase)
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30
Q

Hyperammonemia

A

* Tremor, slurring of speech, blurred vision * Deficiency in urea cycle enzyme. Results in excess NH4+ –> depletes a-KG –> inhibits TCA * Acquired (liver disease) * Hereditary Tx: Benzoate or phenylbutyrate (bind aa)

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31
Q

Ornithine transcarbamoylase deficiency (OTC)

A

XLR, MC urea cycle disorder. OTCase in mito, necessary for production of citrulline from ornithine and CP

  • Results in acc. of cabamoyl phosphate –> inc. orotic acid by UMP synthase (intermediate in pyrimidine syn)
  • orotic acidemia (presence in blood and urine), decr. BUN, hyperammonemia (tremor, slurred speech), irritability, poor muscle tone, seizure
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32
Q

ETC

A

* Recieves donated e- from oxidized carriers (NADH, FADH2) * 4 complexes + CoQ + Cytochrome C * Poisons: * ETC inhibitors (CN-, CO) * Uncoupling agents (Aspirin, brown fat)

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33
Q

CO poisoning

A
  • Headache , cherry-red discoloration (masking cyanosis), seizures. Car exhaust, house fire, etc.
  • CO outcompetes O2 for binding to Hb
  • inhibition of cytochrome oxidase in ETC.

*Decreased O2 saturation; normal PaO2, Left shift

34
Q

CN- poisoning

A
  • Headache , cherry red, weakness/lactic acidosis, cardiac arrest, coma/seizures. House fire.
  • CN- binds and inhibits cytochrome oxidase in ETC, decreases ATP synth.

* normal O2 sat, O2 content of venous and arterial blood are essentially same (no extraction of O2 in tis)

* Tx: Amyl nitrites to oxidize Hb to metHb which combines with CN. Thiosulfate binds cyanide –> thiocyanate, renally excreted

35
Q

Salicylates and alcohol on MT

A

* Hyperthermia * Damages inner mt membrane causing uncoupling and heat generation * Thermogenin/brown fat used to stabilize newborn body temp.

36
Q

HMP shunt

A
  • Requires G6PD and Transketolase
  • Provides source of PRPP for nucleotide synthesis (purine and pyrimidine) and
  • NADPH for: * Neutralizing ROI: Glutathione reductase

* Creating ROI (phagolysosome): NADPH oxidase, Superoxide dismutase, Myeloperoxidase

37
Q

* Free Radical Injury

A

-Ionizing radiation -Hydroxyl FRs -Mt damage -Superoxide FRs -High O2 conc. (repurfusion) -Hydroxyl. superoxide, and peroxide FRs (H2O2) -Drugs -Acetominophen FR (fulminant hepatitis) -CCl4 (liver necrosis)

38
Q

Chronic granulomatous disease

A

-Defiency in NADPH oxidase (X-linked) which is specifically found in PMNs and monocytes. -Test: Serum Nitroblue tetrazolium test (NBT) -Reduced prod. of superoxide (O2) results in absent respiratory burst. Most organisms produce H2O2 which can be used by host to generate HOCl (bleach). -Cat+ organisms (staph) degrade self- produced H2O2. CGD PMNs cannot kill and M0’s infiltrate. M0 wall off infection and form multi-nucleate giant cells

39
Q

Myeloperoxidase deficiency

A

-Deficiency in myeloperoxidase (AR) which is specifically found in PMNs and M0. - Normal respiratory burst (NBT test), but inability to produce HOCl (bleach)– most potent killer

40
Q

G6PD deficiency

A

-Hemolytic anemia (H2O2 induced oxidative damage to RBCs). Heinz bodies (aka. bite cells). -Oxidzed, PPT, Hb –> removed by splenic culling Deficiency in G6PD (X-linked recessive) –> dec. NADPH –> dec. reduced Glutathione. - Glutathione necessary for the met. of H2O2 * Inflammatory H2O2 * Drug induced H2O2

41
Q

Phenylketonuria (PKU)

A

AR deficiency of Phenylalanine hydroxylase Conversion of phenylalanine into tyrosine, BH4 cofactor - Mental/growth retardation, seizures, albinism, eczema, musty body odor -TX: Screen at birth. Low phenyalanine diet w/ tyrosine supplements

42
Q

Alkaptonuria

A

Deficiency in homogenistic acid oxidase (AR, benign) Necessary for degradation of tyrosine to fumarate -Dark CT, brown pigmented sclera, black urine on exp to air, arthralgias

43
Q

Albinism

A
  • Causes: 1. Deficiency in tyrosinase (AR). Enz necessary for the conversion of DOPA –> melanin. 2. Defective melanocyte tyrosine transporters
44
Q

Homocystinuria

A

-Defect in Met –> cytsteine. Caused by: -Deficiency of cystathionine synthase (homocysteine + serine–>cystathionine…–>cysteine) -Impaired binding/deficiency of B6 (cofactor)-tx is B6 tx: decr methionine, incr cysteine, b12, folate -Deficiency of homocysteine methyltransferase (methionine synthase-from homocysteine) - B12 cofactor tx: increase methionine in diet - All AR. Excess homocysteine in urine, tall stature,kyphosis, mental retardation, osteoporosis, lens subluxation, thombosis, AS, stroke

45
Q

Cystinuria

A

AR, defect in PCT and intest AA transporter –> acc. of cysteine in renal tubules. COLA: cysteine, ornithine, lysine, arginine - all are soluble in urine except cysteine can precip - cystine hexagonal kidney stones, precip at low pH, staghorn -Tx: Acetazolamide (alkalizes the urine in the renal tubules and decreases cysteine ppt) Cyanide-nitroprusside urine test dx

46
Q

Maple syrup urine disease

A

Deficiency in a-ketoacid dehydrogenase (TLCFN) Isoleucine, Leucine, and Valine -Mental retardation, Maple syrup urine (smell) Leu: us. degraded to acetoacetate and acetyl CoA (ketogenic) Val, Ile: us degraded propionic acid–>MMA–>succinyl CoA

47
Q

Hartnup disease

A
  • Hereditary defect in transport of neutral aa across renal tubule/epithelial cells. –> Increased urinary excretion of Tryptophan. –> Decreased GI absoroption of Tryptophan. -Dec. Tryptophan –> dec. Niacin –> pellagra -Dermatitis, Dementia, Death
48
Q

Von Gierke disease (Type 1 GSD)

A
  • Deficiency in Glucose-6-phosphatase- needed for cellular release of glucose
  • Infant w/ severe hypoglycemia and lactic acidosis, hypertriglyceridemia, hepatomegaly (high glycogen content)
  • impaired gluconeogenesis- no release of glucose from liver!! (Enzyme bypasses glucokinase)

Tx: freq oral glucose, avoid fructose & galactose

49
Q

Pompe Disease (Type 2 GSD)

A
  • Deficiency in acid maltase aka a-1,4 glucosidase
  • a lysosomal enzyme responsible for breakdown. of some glycogen.
  • Infant w/ progressive muscle weakness, hepatomegaly, **cardiomegaly **–> HF, death
50
Q

Cori Disease (Type 3 GSD)

A
  • Deficiency in debranching enzyme aka a-1,6 glucosidase
  • Infant w/ milder hypoglycemia and hepatomegaly, (high glycogen content).
  • Normal blood lactate due to intact gluconeogenesis; some glycogen met. by glycogen phosphorylase and released by liver.

Tx: high protein diet to feed gluconeogenesis

51
Q

McArdle disease (Type 4 GSD)

A
  • Deficiency in myophosphorylase (skel mm. glycogen phosphorylase)
  • Severe, painful, muscle cramps upon exercise, myoglobinuria w/ exertion, arrhythmia from electrolyte abnorm, No increase in lactate after exercise!
  • symptoms due to acc. of glycogen in muscle
52
Q

Fabry’s disease

A
  • LSD, Deficiency in α-galactosidase A

–> accumulate ceramide trihexoside (XLR)

  • Periph neuropathy (hands/feet), angiokeratomas, CVD and renal failure
53
Q

I cell disease

A
  • Deficiency in a phosphotranferase results in impaired ability to add mannose-6-phosphate (in golgi) to target lysosomal proteins
  • Coarse facial features, clouded corneas, restricted joint movement, and high plasma levels of lysosomal enzymes- FATAL
54
Q

Gaucher’s Disease

A

-LSD, Deficiency in glucocerebrosidase aka ß-glucosidase

–> acc. of glucocerebroside

  • Most common lysosomal storage disease
  • Hepatosplenomegaly, pancytopenia, aseptic necrosis of femur/bone, “Gaucher cells” crumpled tissue paper.
55
Q

Niemann-Pick disease

A

-LSD, Deficiency in Spingomyelinase

–> acc of spingomyelin

-Progressive neurodegeneration and death, hepatosplenomegaly, cherry-red macula, foam cells (lipid laden macrophages)

56
Q

Tay-Sachs disease

A

LSD, Deficiency in Hexosaminidase A

–> acc of GM2 ganglioside

-Progressive neurodegeneration and death, developmental delay, cherry-red macula, onion skin lysosomes (lipid laden lysosomes of neurons)

NO hepatosplenomeg

Ashkenazi

57
Q

Krabbe disease

A

-LSD, Deficiency of B-galactocerebrosidase

–> acc. of galactocerebroside

-Peripheral neuropathy, developmental delay, optic atrophy, globoid cells

58
Q

Metachromatic leukodystrophy

A

-LSD, Deficiency in Arylsulfate A

–> acc. of cerebroside sulfate, in white matter/periph nn

-Central and preipherial demyelination –> dementia and ataxia

59
Q

Hurler’s Syndrome

A
  • Deficiency of **α-L-iduronidase **

–> acc. of GAGs (heparan, dermatan & keratan sufates)

-developmental delay, gargoylism (coarse facial features, macroglossia), airway obstruc, corneal clouding, neurologic dysfunction (hearing loss),

Death in 1st decade (Mucopolysaccharidoses)

60
Q

Hunter’s Syndrome

A
  • Deiciency of Iduronate sulfatase

–> acc. of GAGs (XLR)

  • Mild hurler, Aggressive behavior - NO corneal clouding, slower progress
61
Q

Carnitine deficiency

A
  • Needed to transfer LCFA into the mitochondria for b-oxidation –> toxic accumulation
  • Weakness/hypotonia, hypoglycemic, hypoketotic
62
Q

Acyl-CoA dehydrogenase deficiency (medium chain)

A
  • Deficiency in medium chain acyl-CoA dehydrogenase - mitochondrial enzyme needed for the B-oxidation of FA. (AR)
  • hypoglycemia, hypoketotic upon fasting.
  • Sudden infant death syndrome.
  • Tx: Feedings with slow-release carbs- Cornstarch
63
Q

Cholesterol biosynthesis

A

-3-hydroxy-3-methylglutaryl (HMG Co-A reductase) converts HMG-CoA –> mevalonic acid -HMG CoA synthesized from 3 acetyl CoA molec. -Statins (anti-cholesterol drugs) are HMG CoA reductase inhibitors; block skeletal muscle ubiquinone syn. a coenzyme needed for muscle cell metabolism.

64
Q

Lipoproteins and apolipoproteins

A
  • Lipoproteins- Lipid/proteins complexes that are essential for the trans. of cholesterol, TAGs, and fat-soluble vitamins- ADEK) -(chylomicrosn, VLDL, LDL, IDL, HDL) - Apolipoproteins- increase lipoprotein solubility, activate metabolic enzymes, and mediate the binding of lipoproteins to cell-surface receptors - C (LPL cofactor), A (binds liver remnant receptor)
65
Q

Lipid transport -Syn. in liver from mt Acetyl-CoA (released as VLDLs) -Syn. in intestines from dietary TG (released as chylomicrons w/ apolipoprotein B)

A

• Pancreatic lipase → deg/emulsification of dietary TG in small intestine for packaging. • Lipoprotein lipase (LPL) → deg. of circulating chylomicrons and VLDLs into FFAs or IDLs. 2 paths +Apolipoprotien C (LPL cofactor) • Hepatic TG Lipase (HL) → deg. of chylomicron remnants and IDLs into FFA for liver storage. +Apolipoprotein E (Remnant uptake) • Hormone-sensitive lipase → deg. of TAG stored in adipocytes into FFA (HDL transport).

66
Q

Hyperchylomicronemia (Type 1a/b- Familial dislipidemia)

A

-A- Deficiency in LPL -B- Deficiency in ApoC (LPL cofactor) -Needed for the breakdown of chylomicrons/VLDLs -Resides in capillary walls of adipose and muscle and cleaves TAGs into FFA and glycerol. -High chylomicron/TAG –> creamy serum. pancreatitis, hepatosplenomegaly, puritic xanthomas - Normal LDL and HDL

67
Q

Hypercholesterolemia/hyperbetalipoproteinemia (Type 2a/b familial dislipidemia)

A

-Deficiency in LDL receptor- periph. tissue uptake -Deficiency in ApoB- ligand for LDL receptor binding -High cholesterol (LDL), early atheroscl. disease–> MI, Achilles tendon xanthomas -TAG levels remain normal (clear serum) -Tx: Fibrates- increase prod. of ApoA –> inc. activation of cholesterol acetyltransferase (LCAT) which prod. HDLs

68
Q

Hypertriglyceridemia (Type 4 familial dislipidemia)

A

-Deficiency in VLDL negative feedback mechanism –> Hepatic overproduction of VLDL- (from excess dietary fats) -High cholesterol (VLDL) and TAG (turbid/foamy plasma), pancreatitis -Tx: Fibrates- increase prod. of ApoA –> inc. activation of cholesterol acetyltransferase (LCAT) which prod. HDLs

69
Q

Abetalipoproteinemia

A

-Deficiency in ApoB– a cofactor needed for chylomicron secretion—> TAG acc. in enterocytes. (AR) -Failure to thrive, steatorrhea, ataxia, and acanthocytosis -Tx: Vitamin E- helps restore lipoprotien prod.

70
Q

Dysbetalipoproteinemia (Type 3 familial dislipidemia)

A
  • Deficiency in ApoE- ligand for cholesterol remnant hepatic uptake -elevated VLDL levels -Palmer xanthomas (turbid serum); seen with diabetes
71
Q

Hypercholesterolemia and MI

A

-Subendothelial space accumulates lipoproteins. Lipoproteins get chemically modified (i.e. oxidized) which initiates an inflammatory response and phagocytosis by M0 –> foam cells. Release of PDGF, TNF, and IL-1 results in recruitment of platelets and production of ECM in the vesseles –> formation of fibrotic plaque -> actue MI

72
Q

Unonjugated vs. conjugated hyperbilirubinemia

A
  • Bilirubin is the breakdown product of heme. It is conjugated with a glucoronic acid in the liver to increase its solubility in water
  • Unconjugated hyperbilirubinemia - high RBC breakdown or decreased liver function (Gilberts)
  • Conjugated hyperbilirubinemia - hepatic obstruction preventing excretion into bile (urine urobilinogen (product of gut flora bilirubin breakdown)
73
Q

Fat soluble vitamins (can accumulate in fat –> toxic)

A
  • ADEK -A (retinol)- visual pig. and normal diff. of epithelial cells into specialized cell types
  • D (D3)- intestinal absorption of Ca2+ and phos.
  • E- antioxidant that protects RBCs from FR dam.
  • K- catalyzes the carboxylation/act. of clotting factors 2,7,9, and 10.
74
Q

Water soluble vitamins

A
  • B,C, Biotin, and Folate
  • B (Thiamine, riboflavin, niacin, pantothenate, pyridoxine, cobalamin)
  • C (absorbic acid)- proline hydroxyation in collagen synthesis, dopa –> NE conversion, Iron absorption
  • Biotin (B7) - cofactor for carboxylation enzymes
  • Folate (B9) - synthesis of nucleic acids
75
Q

Vitamin B1 (thiamine)

A
  • Cofactor for dehydrogenase enzymes (pyruvate dehydrogenase, a-ketoglutarate dehydrogenase, transketolase (HMP shunt), Branched AA dehydrogenase)
  • Deficiency impairs glucose met–> ATP depletion, worsened by glucose infusion, Alcoholics- Primarily affects brain and heart.
  • Wernicke-Korsakoff synd - confusion, opthalmoplegia, ataxia, and personality change.
  • Beriberi - cardiac failure, DCM, sym. muscle wasting, edema
76
Q

Vitamin B2 (riboflavin)

A
  • FAD, FMN, Cofactor in redox reactions (succinate DH in TCA) and prod of FADH2
  • Deficiency impairs ATP prod.
  • Cheilosis (inflam/scaling of lips)
  • Corneal vascularization
77
Q

Vitamin B3 (niacin)

A
  • Derived from tryptophan, synthesis requires B2 and B6
  • Constituent of NAD+
  • Deficiency results from impaired absorption of tryp. (Hatnup synd), deficiency in B6 (INH), malignant carcinoid syndrome (increased Trp metab)
  • Glossitis (tongue inflammation)
  • Pellagra (dermatitis, dementia, diarrhea)
  • Lowers VLDL, raises HDL, facial flushing (due to PGs), hyperglycemia, hyperuricemia
78
Q

Vitamin B5 (pantothenate)

A
  • Cofactor for acyl transfers (CoA) and FA synthase
  • Deficiency is rare
  • Alopecia
  • Dermatitis
  • Adrenal insufficiency

CoA used in synth of vit. A, D, steroids, heme A, fatty acids, amino acids, proteins

79
Q

Vitamin B6 (pyridoxine)

A
  • Cofactor needed for transamination rxns (ALT and AST), decarboxylation rxns, glycogen phosphorylase, and synth of cystathionine, heme, niacin, histamine, and NTs: GABA, 5-HT, Epi, Ne, DA
  • Deficiency results in impaired protein metabolism, glucose level maintenance, RBC syn,
  • Convulsions/hyperirritability
  • Peripheral neuropathy (Induced by INH and OCPs)
  • Sideroblastic anemia (impaired Hb synth and iron excess, microcytic hypochromic)
80
Q

Vitamin B12 (cobalamin)

A
  • Cofactor for synthesis of methionine (from homocysteine+folate) and the regeneration of reduced folate
  • Deficiency impairs DNA synthesis (though stored in large reserve quantities) and results in neuronal acc. of methymalonic acid
  • Macrocytic/megaloblastic anemia
  • Peripheral neuropathy/ataxia
81
Q

Vitamin B9 (Folic acid)

A

-Converted to THF; used as coenzyme for methylation reactions -Deficiency impairs DNA/RNA synthesis (small reserve store; depleted in alcoholics & pregnancy) -Macrocytic, megaloblastic anemia -Neural tube defects

82
Q

Biotin

A

-Cofactor for carboxylation enz. (pyruvate carb., Acetyl CoA carbox., Propionyl CoA carboxylase - Deficiency in rare (caused by excessive egg consumption) impairs gluconeogenesis, FA synthase regulation and DNA syn. -Dermatitis/enteritis -alopecia

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