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Flashcards in Amino Acids Deck (19):
1

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
NE-->Epi SAM

2

Which enzyme does carbidopa inhibit?

dopa decarboxylase

3

Cortisol stimulates which step?

NE-->Epi

4

What are the breakdown products of dopamine, NE, and epinephrine?

dopamine-->homovanillic acid
NE-->VMA
epi-->metanephrine

5

What are the essential amino acids?

Private (PVT) TIM HaLL
Phenylalanine
valine
threonine
tryptophan
isoleucine
methionine
histidine
leucine
lysine
**must eat!

6

What are the acidic AA? Basic AA?

Acid AA: aspartate, glutamate
Basic AA: Arginine, Lysine, Histidine

7

What are the charges of the basic AA?

(+) except for histidine which is neutral

8

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

9

What is arginine transformed into?

urea
creatinine
nitric oxide (w/ BH4)

10

What is tryptophan converted into?

niacin-->NAD+ (B6)
serotonin (B6, BH4)-->melatonin

11

What is histidine converted into?

histamine (Vit b6)

12

What is glycine converted into?

porphyrin-->heme (B6)

13

What is glutamate converted into?

GABA (B6).
Glutathione

14

Where does the urea cycle take place?

hepatocytes
CPSI in mitochondria. Then carbamoyl phosphate transferred into cytosol for rest of urea cycle.

15

What is a commonly deficient enzyme of the urea cycle?

orthinine transcarbamylase.
carbamoyl phosphate + ornithine-->citrulline.

16

Describe the features of ornithine transcarbamylase deficiency.

X-linked recessive
Hepatic Encephalopathy (b/c of buildup of ammonium)
orotic acid in blood & urine
BUN decreased b/c can't make urea

17

2 causes of hepatic encephalopathy?

b/c of increased ammonia

1. liver failure
2. OTC deficiency (urea cycle)

18

What are the features of hepatic encephalopathy?

slurring speech
somnolence
vomiting
cerebral edema
blurred vision

19

What is the treatment for ornithine transcarbamylase deficiency?

low protein diet
phenylbutyrate or benzoate (increase excretion of AA)
biotic (stimulates OTC)