PROTEIN METABOLISM I Flashcards
continuous degradation and resynthesis of all cellular proteins
protein turnoever
susceptibility of a protein to degradation is expressed as its
HALF LIFE
half-lives for liver proteins range from under
30 mins to over 150 minutes
proteins with half lives over 100 hours include
ALC
aldolase, lactate dehydrogenase, and cytochromes
two major pathways that degrade intracellular proteins of eukaryotic cells
lysosomal degradation
ubuiquitin
lysosomes have a selective pathway which is activated only after a prolonged fast, that imports and degrades cytosolic proteins containing the pentapeptide KFER1 (lys-phe-glu-arg-gln) or a closely related sequence
Lysosomal degredation
proteins are marked for degradation by covalently linking them to ____________
ubiquitin
3 amino acids that are not metabolized in the liver
Valine Leucine Isoleucine
Valine Leucine Isoleucine are metabolized in the __________
brain and muscles
amino acids that can not be synthesized by the body so they must be provided in the diet
essential or indispensible amino acids
amino acids can be synthesized by the body so they need not be provided in the diet
non-essential or dispensible
semi-essential amino acid
arginine
3 enzymes that occupy central positions in amino acid biosynthesis
G-G-A
glutamate dehydrogenase
glutamine synthetase
aminotransferases
3 enzymes that occupy central positions in amino acid biosynthesis
used to synthesize glutamic acids
glutamate dehydrogenase
3 enzymes that occupy central positions in amino acid biosynthesis
used to synthesize glutamine
glutamine synthetase
3 enzymes that occupy central positions in amino acid biosynthesis
enzymes that are used for transamination
can be used to synthesize many other amino acids
aminotransferases