Exam 4 Review Flashcards
Major source of amino acids in pool
Body protein (200 g/day)
Hereditary pancreatitis
Overactive trypsin (lack of inhibitor) in the pancreas
Enteropeptidase
Cleaves trypsinogen to activate it to trypsin
Amino acid absorption
Sodium linked transporters for groups of amino acids with similar characteristics
Cystinuria
Defective cysteine (and lysin) transporter in the kidney which leads to lack of cysteine
E3 Ub ligase
Recognizes proteins and are polyubiquitinated at a lysine side chain
Ubiquitinated amino acid
Lysine
M end rule
If a protein has a methionine at the end, it is degraded the slowest
DUB
Deubiquitinase, recycles ubiquitin in single Ub units
Proteosome
Degrades proteins into 7-10 amino acid peptides
What happens when you lack essential amino acids
Break down body protein (muscle)
Negative nitrogen balance
Happens in absence of other fuels (trauma), protein is used for energy and making glucose
Positive nitrogen balance
Increased protein deposition (building muscle, growing, etc)
PLP
Vitamin B6, helps with aminotransferase reactions
Location of urea cycle
Periportal region of the liver
NAG (n-acetyl glutamate)
Synthesis from acetyl CoA and glutamate (stimulated by arginine), required for CPSI activity
OTC deficiency
X-linked, can’t do urea cycle, arginine supplement, high starch diet
Glutamine synthase
Found in perivenous liver and brain and muscle for detoxifying blood
Treatments of hyperammonemia
- Compounds (benzoate or penylbutyrate) that remove certain non-essential aas (need to use NH4 by synthesizing them)
- Limit the protein intake and use starch
- Supplement with arginine (except argininase deficiency)
Amino acids that muscle uses for energy
Branched chain amino acids (isoleucine, valine, leucine) liver does not have branched chain amino acid transferase to utilize these aas
Maple syrup urine disease
Defect of branched chain keto acid dehydrogenase
PKU defects
Phenylalanine hydroxylase or dihydrobiopterin reductase, High levels of phenylalanine interfere with brain development and function
Treatment of PKU
Restrict phenylalanine, supplement tyrosine
Vitamin B12 deficiency (4 ways)
- Diet low in vitamin B12
- Lack of intrinsic factor
- Poor absorption in intestine
- Lack of conversion to active (adenosyl or methyl) forms
Synthesis of dopamine
Decarboxylation of dopa, S-adenosyl methionine used to make epinephrine for norepinephrine
Tyrosinase
Used to make melanin, lacked in albinism
Thyroid peroxidase
Found in thyroid, forms thyroxine
Amino acids used to inter convert forms of TH4
Serine and glycine
Homocystinuria
Lack of cystathionine synthase or lack of folate or B12
Synthesis of phosphocreatine
Arginine plus glycine makes guanidinoacetic acid SAM methylates
Where components of purines come from
2 Cs and an N- glycine 2 Ns glutamine 2 Cs N10 formyl TH4 N aspartate C CO2
Pyrimidine component origins
Carbamoyl phosphate and aspartate
Gout
Elevated Uric acid, HGPRT defect, G6P dehydrogenase defect
Allopurinol
Treatment of gout, inhibitor of xanthine oxidase
Lesch-Nyhan syndrome
Complete lack of HGPRT
Adenosine deaminase deficiency
SCID
Ribonucleotide reductase
Uses NADPH to reduce ribose to deoxyribose
Protein use in starvation
Used a lot in early starvation (75 g/day) and decreases as starvation continues (20 g/day)
3rd stage of starvation
Glycogen almost completely depleted, muscle decreases glucose use increases FA use, proteins degraded to amino acids, TAGs produce FAs for fuel and glycerol for glucose production
4th stage of starvation
Brain begins to use ketone bodies, less overall gluconeogenesis
5th phase of starvation
Brain almost exclusively uses ketone bodies, erythrocytes and renal medulla still use glucose
Sulfonylureas
Inhibit ATP dependent calcium channels (trigger insulin production)
Glinides
Inhibit K+ channels
Incretin analogues
Mimic gut hormone, increase insulin production
DPIV inhibitors
Inhibit the degradation of incretins
Alpha glucosidase inhibitors
Block glucose uptake
SGLT2 inhibitors
Inhibit glucose reuptake in the kidney
Metformin
Blocks gluconeogenesis in liver and increases insulin receptor sensitivity
GLP and GIP
Incretins, regulators of the K+ channel
Insulin production
Preproinsulin->Proinsulin-> Insulin
Insulin signaling
Gluose transport and glycogen synthesis are through lipid signaling
Gene expression is controlled with protein signaling
What insulin decreases
Blood glucose, glycogen phosphorylase activity, gluconeogenic reactions, HSL
What insulin increases
Glycolysis, FA synthesis, lipoprotein lipase, glucose in adipocytes, aa uptake
Lipid triad
High TAG
High VLDL/LDL
Low HDL
