Amino Acid Metabolism and associated diseases Flashcards
AA synthesis:
- Glutamate
- Glutamine
- Aspartate
- Asparagine
- Alanine
- Arginine
- Glutamate
- a-ketoglutarate, ammonia, NADPH, glutamate dehydrogenase
- Glutatmine
- glutamate, ammonia, ATP, glutamine synthetase
- Aspartate
- oxaloacetate, glutamate, aminotransferase
- Asparagine
- aspartate, ATP, glutamine, asparagine synthetase
- Alanine
- pyruvate, glutamate, aminotransferase
- Arginine
- urea cycle* argininosuccinate, argininosuccinate lyase
Synthesis of Proline and Ornithine starts with
reduction of glutamate
Proline functions:
- Sharp angles in proteins (e.g. collagen)
- Antioxidant (Pro-to-Glu- releases NADPH)
- Possibly osmolyte
Enzyme deficiency causes metabolic cutis laxa syndrome, a rare skin disorder
the starting material for serine synthesis
serine is the starting material for
3-phosphoglycerate
cysteine and glycine
* Phosphoglycerate dehydrogenase
* Aminotransferase
* Phosphatase
THF (or H4 Folate) is tetrahydrate folate, a cofactor derived from__________
Vit B, FOLIC ACID
produces NADH (energy) and is PLP dependent. In vivo it only functions in the degradation of glycine.
The glycine cleavage enzyme reaction
Folate (Vit B9) is reduced by
Folate and Tetrahydrofolate (THF) consist of 3 groups
dihydrofolate reductase to form THF
- A pteridine,
- an amino benzoate
- a chain of one or more glutamate residues
THF carries _______ groups
THF carried ____ can be at various ________
1-C
C; oxidation states
B12 or B9 (folate) deficiency/ deficiency of Cystathionine synthase
a rare methionine malabsorption disease:
- Homocysteineuria, cardiovascular disease
- Oasthouse Syndrome
SECONDARY METABOLITES OF Amino Acids
- Asp
- Cys
- Glu
- Gly
- His
- Lys
- Met
- Orn
- Phe
- Ser
- Trp
- Tyr
- Arg
- Urea, creatine/creatine, NO
- Asp
- NMDA
- Cys
- Taurine, Hypotaurine, PAPS, thiocysteine
- Glu
- GABA, GSH
- Gly
- Heme, Oxalate, GSH, creatine/creatinine
- His
- Histamine
- Lys
- Carnitine
- Met
- S-adenosylmethionine, carnitine, creatine/creatinine, spermine, spermidine, choline
- Orn
- Putrescine
- Phe
- See tyrosine
- Ser
- Selenocysteine, ethanolamine, choline, betaine
- Trp
- Kynurenine, xanthurenine, serotonin, melatonin, nicotinamide
- Tyr
- Dopamine, norepinephrine, epinephrine, melanin, thyroid hormones
Selenocysteine (SeCys) is synthesized from
Serine
cotranslationally produced
aromatic quinones (tyrosine metabolites)
Melanin
(contains Cu++) Deficiency of enzyme tyrosinase or Cu cause Albinism
a rare Parkinsonism like mental disorder- can be treated with L-dopa
Tyrosine hydroxylase deficiency
Tyrosinase converts tyrosine to L-Dopa normally during melanin synthesis and could compensate for Tyrosine hydroxylase deficiency for catecholamine synthesis. (But two enzymes are present in different cell types)
critical for neurotransmitters synthesis, and is used as drug
SAM
serotonin
- Neurotransmitter
- target of CNS active dugs (Its reuptake into the neuron is the target of Prozac)
- also vasoactive (via NO synthetase)
Melatonin
- Induces sleep
- Regulates Circadian Rhythm
is a small molecule neurotransmitter (like Serotonin, Epinephrine (adrenaline) and Dopamine) made by decarboxylation of histidine
Histamine
- Produced in Mast Cells and basophils
- Important part of the inflammatory response/ immune response
- a powerful vasodialator
- also helps regulate physiological function in the gut; sleep; and the sexual response
Glutathione:
- a reductant; e.g. protect RBCs from peroxidation? Use of GSH Peroxidase (recall selenocysteine)
- Regenerate GSH using glutathione reductase and NADPH (from the hexose monophosphate shunt)
- Conjugated with drugs to make them more soluble for clearance by the kidney
- Transport of aa across membranes
