amino acid metabolism

Question 1

brokendown amino acids can go to which two pathways and what can they become in those pathways

Answer 1

Glucogenic:
pyruvate, oxaloacetate, fumarate, succinyl coA, alpha-ketoglutarate

Ketogenic: acetly coA, acetoacetyl coA

Question 2

ketogenic only bound a.a.s

Answer 2

leucine (L), lysine (K)

Question 3

glucogenic and ketogenic a.a.s

Answer 3

Ile, thr, phe, tyr, trp

Question 4

first general step of aa metab is to transfer alpha amino group but this does not occur in which amino acid

Answer 4

lysine (Y)

Question 5

acute lymphoblastic leukemia cells have low asparagine synthetase activity so use what to treat

Answer 5

asparaginase to lower amounts of asparagine so cells have problems and die
(asparagineaspartateoxaloacetate)

Question 6

pyruvate is entry point for what 3 a.a.

Answer 6

ala, ser, cys

cystine also goes to taurine to make bile salts–glycine as well

Question 7

if missing glyoxylate transaminase in glycine metab, can get

Answer 7

kidney stones from built up oxalute (oxaluria type I)

Question 8

3-phosphoglycerate forms what three a.a.s

Answer 8

serine, cystine, and glycine

Question 9

in conjunction with serine, what does homocysteine synthesize, and if there is a defect in cystathionine beta-synthase (homocystinuria) what happens

Answer 9

cysteine! defects cause high homocystinuria increasing risk for CHD, arteriosclerosis, and dislocation of eye lens

(treat with vitamin B6 PLP)

Question 10

methionine synthase converts methionine to? and relies on what vitamin

Answer 10

homocysteine and relies on cobalmin (B12)

Question 11

branched chain aa include what, are metabolyzed where, and produce how much energy?

Answer 11

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)

Question 12

BCKA dehydrogenase rxn is similar to

Answer 12

pyruvate DH rxn (so for children with maple syrup urine disease, things that benefit pyruvate rxn will benefit this (B1))

Question 13

maple syrup urine disease cause by and results in

Answer 13

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

Question 14

deficiency in vitamin B12, cobalmin, leads to

Answer 14

build up of methylmalonyl coA

other B12 is conversion of homocysteine to methionine

Question 15

phenylalanine converted to tyrosine by? with what cofactor? and a defectiveness causes what?

Answer 15

phenylalanine hydroxylase
tetrahydrobiopterin (B4) for hydroxylation
PKU

Question 16

symptoms of PKU (phenylketouria)

Answer 16

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

Question 17

PKU dietary restrictions

Answer 17

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

Question 18

defect in homogentisate oxidase forming dark pigment that discolors urine

Answer 18

alcaptonuria–homogentisate will build up and form Ochronotic pigments which can cause joint pain later in life

Question 19

Type 1 tyrosinemia (tyrosinosis) is caused by a genetic deficiency where, symptoms, and is treated with what?

Answer 19

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)

Question 20

Type II tyrosinemia

Answer 20

genetic deficiency of tyrosine aminotransferase, eye and skin lesions, and treat with a low tyrosine, phenylalanine diet

Question 21

neonatal tyrosinemia

Answer 21

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

Question 22

tryptophan degredation produces what, with what PLP dependent intermediate

Answer 22

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)

Question 23

thr, met, ile, and val

Answer 23

propionyl coA

Question 24

leu

Answer 24

lysHMG coA, then acetoacetate and acetyl coA (ketogenic only)

Question 25

lys

Answer 25

acetyl coA via complex pathway (ketogenic only)

Question 26

trp

Answer 26

acetyl coA and ala

Question 27

pro and his

Answer 27

to glutamate

Question 28

ala

Answer 28

to pyruvate by transamination

Question 29

arg

Answer 29

urea and glutamate

Question 30

asp and asn

Answer 30

oxaloacetate by transamination