amino acid metabolism Flashcards
(30 cards)
brokendown amino acids can go to which two pathways and what can they become in those pathways
Glucogenic:
pyruvate, oxaloacetate, fumarate, succinyl coA, alpha-ketoglutarate
Ketogenic: acetly coA, acetoacetyl coA
ketogenic only bound a.a.s
leucine (L), lysine (K)
glucogenic and ketogenic a.a.s
Ile, thr, phe, tyr, trp
first general step of aa metab is to transfer alpha amino group but this does not occur in which amino acid
lysine (Y)
acute lymphoblastic leukemia cells have low asparagine synthetase activity so use what to treat
asparaginase to lower amounts of asparagine so cells have problems and die
(asparagineaspartateoxaloacetate)
pyruvate is entry point for what 3 a.a.
ala, ser, cys
cystine also goes to taurine to make bile salts–glycine as well
if missing glyoxylate transaminase in glycine metab, can get
kidney stones from built up oxalute (oxaluria type I)
3-phosphoglycerate forms what three a.a.s
serine, cystine, and glycine
in conjunction with serine, what does homocysteine synthesize, and if there is a defect in cystathionine beta-synthase (homocystinuria) what happens
cysteine! defects cause high homocystinuria increasing risk for CHD, arteriosclerosis, and dislocation of eye lens
(treat with vitamin B6 PLP)
methionine synthase converts methionine to? and relies on what vitamin
homocysteine and relies on cobalmin (B12)
branched chain aa include what, are metabolyzed where, and produce how much energy?
val, leu, Ile
metabolism begins in skeletal muscle, NOT liver, and 1 mol branched chain aa (BCAA) yeilds 101 ATP!
(amino group carried back by ala)
BCKA dehydrogenase rxn is similar to
pyruvate DH rxn (so for children with maple syrup urine disease, things that benefit pyruvate rxn will benefit this (B1))
maple syrup urine disease cause by and results in
branched-chain alpha-keto acid (BCKA) dehydrogenase genetic defect resulting in build up of BCAAs (Lue, Ile, Val) and alpha-ketoacids.
causes vomiting, lethargy, and severe brain damage in babies who generally die 1 year
deficiency in vitamin B12, cobalmin, leads to
build up of methylmalonyl coA
other B12 is conversion of homocysteine to methionine
phenylalanine converted to tyrosine by? with what cofactor? and a defectiveness causes what?
phenylalanine hydroxylase
tetrahydrobiopterin (B4) for hydroxylation
PKU
symptoms of PKU (phenylketouria)
elevated Phe in blood and urine, diagnose via mass spec for normally born baby.
irreversible mental retardation, delayed phychomotor maturation, tremors, seizures, eczema, hyperactivity
mousy odor
comptetive interaction of phe with brain aa transport system and impaired myelin synth
PKU dietary restrictions
Lofenalac synth supplement with dietary nutrients aside from phe,
avoid meat,
kuvan (synth version of tetrahydrobiopterin–no classic patients respond),
supp with large aa that compete with phe
defect in homogentisate oxidase forming dark pigment that discolors urine
alcaptonuria–homogentisate will build up and form Ochronotic pigments which can cause joint pain later in life
Type 1 tyrosinemia (tyrosinosis) is caused by a genetic deficiency where, symptoms, and is treated with what?
genetic deficiency of fumarylacetate hydrolase causing liver failure ( toxic succinylacetone accumulation), cabbage like odor, death within 1 year
treated with NTCB (blocks 4-hydroxyphenylpyruvate dioxygenase) to cause accumulation of hawkinsinuria (less harmful)
Type II tyrosinemia
genetic deficiency of tyrosine aminotransferase, eye and skin lesions, and treat with a low tyrosine, phenylalanine diet
neonatal tyrosinemia
HPP dioxygenase activity is low below berfore birth and rises until near normal at birth. HHP DO is vitamin c dep so low protein diet with supp ascorbic acid
tryptophan degredation produces what, with what PLP dependent intermediate
produces formate, alanine, and acetyl coA
uses kynurenine as intermediate and forms kynureninic acid excreted in urine (and kynurenine hydroxylase is used to test for PLP deficiency)
thr, met, ile, and val
propionyl coA
leu
lysHMG coA, then acetoacetate and acetyl coA (ketogenic only)
