ammonia metabolism Flashcards
disease of negative nitrogen balance
anorexia, Kwarshiorkor
most important amino acid
Glutamate –> aplha keto glutarate
donates N to urea cycle
Aspartate
key in gluconeogenesis
Alanine
transports N to liver
Glutamine
Body uses these fuels in the FED state
fatty acids and carbohydrates
Used in FASTED state for energy
amino acids (gluconeogenesis)
important in use of amino acisa as fuel
alanine
These enzymes pick up free NH4+
Glutamate DH and Glutamine synthase
oxaloacetate of ammonia cycle
ornithine
key regulatory enzyme of urea cycle
CPSI
defect in arginosuccinate synthetase
add arginase –> allows cycle to move
defect in argininosuccinate lyase
add excess arginosuccinate lyase - it will get peed out
3 enzymes that fix N to carbon
CPSI, glutamate dehydrogenase, glutamine synthase
buildup of this amino acid activates this enzyme
arginine - creates NAG
all disorders of urea cycle result in this
elevated blood NH4+
Disorder with elevated urinary orotic acid due to buildup of carbamoyl phospate
Ornithine Transcarbamoylase enzme def.
HHH syndrome, elevated ammonaemia, ornithaemia, citrullinameia
defective transporter
substrates of homocitrulline
carbamoyl phosphate and lysine
test for ammonia
free ammonia and BUN
elevated orotic acid sign of
defect past CPT1, excess carbamoyl phosphate and aspartate
make amino acids excreted in urine
benzoic acid (glycine) and Pheylbutyrate (glutamine)
