Flashcards in Amino Acids Deck (19):
Describe how you get from phenylalanine to epinephrine.
phenylalanine-->tyrosine via phenylalanine hydroxylase, requires BH4
tyrosine-->DOPA via tyrosine hydroxylase, requires BH4
(note: dopa-->melanin via tyrosinase)
DOPA-->dopamine via dopa decarboxylase Vit B6
dopamine-->NE, requires Vit C
Which enzyme does carbidopa inhibit?
Cortisol stimulates which step?
What are the breakdown products of dopamine, NE, and epinephrine?
What are the essential amino acids?
Private (PVT) TIM HaLL
What are the acidic AA? Basic AA?
Acid AA: aspartate, glutamate
Basic AA: Arginine, Lysine, Histidine
What are the charges of the basic AA?
(+) except for histidine which is neutral
What are the functions of the basic AA?
periods of growth ARG and HIS
histones (bind neg. charge of DNA) ARG and LYS
nuclear localization signals
What is arginine transformed into?
nitric oxide (w/ BH4)
What is tryptophan converted into?
serotonin (B6, BH4)-->melatonin
What is histidine converted into?
histamine (Vit b6)
What is glycine converted into?
What is glutamate converted into?
Where does the urea cycle take place?
CPSI in mitochondria. Then carbamoyl phosphate transferred into cytosol for rest of urea cycle.
What is a commonly deficient enzyme of the urea cycle?
carbamoyl phosphate + ornithine-->citrulline.
Describe the features of ornithine transcarbamylase deficiency.
Hepatic Encephalopathy (b/c of buildup of ammonium)
orotic acid in blood & urine
BUN decreased b/c can't make urea
2 causes of hepatic encephalopathy?
b/c of increased ammonia
1. liver failure
2. OTC deficiency (urea cycle)
What are the features of hepatic encephalopathy?