A.A. catabolism Flashcards
What 2 A.A. don’t undergo deamination directly?
Lys, Pro
> @KG?
Gln, Glu, Arg, His, Pro
Histidase deficiency >
Histidinemia: speech difficulty
Limiting His impairs growth
> OXAC?
Asn, Asp
> Acetoacetate?
Lys, Leu
Ketogenic
Lysine metabolism occurs in _
Liver
Hyperlysinemia >
Saccharopine DH defect
Mental, physical retardation
> Pyruvate?
Ala, Gly, Ser, Cys, Thr
Ser > Gly via ?
Serine + THF > Gly + methylene THF via serine hydroxymethyl transferase
T/F: Threonine catabolism gives both keto/glucogenic products.
True
BCAA catabolism
Where does it occur?
Leu, Ile, Val
Muscle
BCKADH needs 5 cofactors
lipoic acid, NAD, FAD, TPP, CoA
Maple syrup urine disease
- Defect in BCKADH or cofactors
- Ketoacids accumulate and excreted in urine
- Maple syrup odor
Sweaty feet syndrome
- Defect in leu metabolism
- Deficiency in isovaleryl CoA DH
- Isovaleryl CoA > unsaturated acyl CoA
- Accumulation of isovaleric acid
Aromatic A.A.
Phe, Tyr
Phenylketonuria
- Deficiency in Phe-hydroxylase
- Hyperphenylalaninemia
- Phe accumulates > transamination of Phe > phenyl acetate and phenyl lactate, phenyl pyruvate
Alkaptonuria(black urine)
- Deficiency in homogentisic dioxygenase
- HA accumulates, excreted in urine, + O2 > black urine
- Inflammation in joints
Albinsim
- Deficiency of tyrosinase isoenzyme in CNS
- Improper hydroxylation of tyr
- Not deficient in dopamine
3OH-anthranilic acid is a precursor of
NAD
Deficiency in Trp oxygenase/niacin
pellagra
Deficiency in kynureninase/B6
- Excretion of kynurenine in urine…green urine
SAM is used in (3)
- Melatonin from serotonin
- Epinephrine from nor
- PC synthesis
Cysteine can yield many products…
- Pyruvate
- Oxidized cystine
- Cysteic acid > Taurine
- Cysteic acid deamination > PAPS
- B-mercapto-ethyl amine…+ pantothenic acid > CoA
Homocystinuria
- Deficiency in cystathionine synthase
- Homocysteine accumulates
- Thiolactone > cardiovascular problems
- Atherosclerosis
