Amino Acid Metab: Notes Flashcards
(52 cards)
AAs derived from intermediates of glycolysis
Serine, glycine, cysteine, alanine
SCAgLY
AAs derived from krebs cycle (alpha-ketoglutarate)
glutamate, glutamine, histidine, arginine, proline
GLUe HAPpens
AAs derived from krebs cycle (oxaloacetate)
aspartate and arginine
OAAAAA
the carbon skeletons of AA are usually converted to ___
carbohydrates and ketones
the N of AA is usually converted to
ammonia via the urea cycle
relative susceptibility of a proptein to degradation
half-life
differentiate housekeeping enzymes from regulatory proteins
HOUSEKEEPING: slow = 100h
REGULATORY: fast = 2h
what proteins are usually targeted for RAPID DEGRADATION
PEST sequences:
Proline, glutamatE, Serine, and Threonine
intracellular protease that hydrolyzes INTERNAL PEPTIDE BONDS and degrades the resulting peptides to amino acids
endopeptidases
intracellular protease that removes the AA sequentially from amino-termini
aminopeptidases
intracellular protease that removes the AA sequentially from carboxy-termini
carboxypeptidases
type of glycoprotein degraded after a loss of a SIALIC ACID MOIETY from the NON-REDUCING end of an oligosaccharide chain
blood glycoprotein
blood glycoprotein is degraded after a loss of ___ from ____
type of glycoprotein degraded after a loss of a SIALIC ACID MOIETY from the NON-REDUCING end of an oligosaccharide chain
type of glycoproteins internalized the liver cells degraded by lysosomal proteases
asialoglycoproteins
how are asialoglycoproteins degraded?
internalization by hepatocyte and degraded by LYSOSOMAL PROTEASES
the degradation of what kind of glycoproteins is INDEPENDENT of ATP?
blood glycoproteins and asialoglycoproteins
what kind of proteins are degraded WITH the use of ATP?
regulatory proteins with short half-lives
or
misfolded proteins
= short half = need energy to get rid of them
what are the components of the enzyme system that is responsible for attaching ubiquitin?
E1: activating enzyme
E2: ligase (500 types)
E3: transferase (catalyzes the very transfer of ubiquitin)
where and how is UBIQUITIN attached?
attached by NON-ALPHA PEPTIDE BONDS
- located between:
(1) carboxy terminal of U
(2) eta amino groups of LYSYL residues in target proteins
what PREVENTS the attachment of ubiquitin?
Amino terminals MET and SER
what PROMOTES the attachment of uniquitin?
ASP and ARG
what structures undergo polyubiquitination
soluble proteins, kinds of LIGASE
where does the degradation of ubiquitin-tagged proteins occur?
proteasome
what organ generates HALF of the body’s protein pool?
muscle
