New Material Flashcards
Amino acids are used for protein synthesis __ ____
in vivo, only when the protein is needed
What happens to excess AA?
catabolized
Where do N and C themes occur?
liver
N theme
AA deamination and ammonia detoxification. Urea synthesis in mammals
C theme
breakdown of carbon skeleton
N theme steps
- remove primary amino group from AA
- synthesis of alpha-keto acid
3.detoxification of ammonia
glutamate dehydrogenase (GDH)
deamination of glutamate, a redox rxn. Plays a role in almost all AA
transaminase (aminotransferase)
take AA and α-keto acid to synthesize new AA and new α-keto acid
What do almost all transaminases use?
α-ketoglutarate and glutamate
What B vitamin do transaminases require for catalytic function?
B6 = pyridoxal phosphate
AST
aspartate amino transferase
ALT
alanine amino transferase
What do AST and ALT levels do?
Should be very low levels in bloodstream. Indicate liver damage
AST and ALT are _________
equimolar
Normal AST levels
8-50 U/L
Normal ALT levels
7-55 U/L
What is released faster in liver damage?
AST, almost 2X faster
Ratio of AST:ALT to be liver issue
> 2
Ratio of AST:ALT to be non-liver issue (but still issue)
> 5
Deamination of serine
serine –> pyruvate by serine dehydratase
Deamination of threonine
threonine –> α-ketobutyrate by threonine dehydrates
Prosthetic group for serine and threonine dehydratase?
pyridoxal phosphate
Where does detoxification of ammonia occur?
cytosol, with some steps in mitochondria
Where is alanine generated?
muscle
