Exam 3 Flashcards
What is lysosomal degradation, and what is its optimal pH?
involves several proteases
pH= 5 and is much less active at a pH of 7 (pH of cytoplasm) bc it won’t work if it’s not in the lysosome
How does lysosomal degradation differ in well-nourished versus starving cells?
In well-nourished cells, lysosomal degradation is nonselective
In starving cells, selective protein degradation occcurs, especially in organs like the liver and kidney (NOT brain)
When one is in starvation what sequence mediates it in lysosomal degradation?
Mediated via KEFRQ sequence in proteins
Where is lysosomal activity increased?
- Muscle wasting
(use it or lose it- lack of use, injury)
*arthritis
Draw PLP
lec 8; slide 11
What are the two stages in which transamination rxns occur
Ala + 𝛼-KG↔︎ pyruvate + Glu
stage 1
Ala +PLP↔︎ pyruvate + pyridoxiamine-P
stage 2
pyridoxamine-P + 𝛼-KG↔︎ Glu+ PLP
What are some transamination rxns (AND DRAW):
Alanine↔︎
Aspartic acid↔︎
Glutamic acid↔︎
Alanine↔︎ pyruvate
Aspartic acid↔︎ OXAC
Glutamic acid↔︎ 𝛼-KG
what is the difference between transamination, tautomerization, and hydrolysis
Glutamate DH
removes NH4⁺ by oxidate deamination
✿ Glu+ NAD(P)⁺ ↔︎ ⍺-KG + NH4⁺ + NAD(P)H
✿ reversible
✿High Km for Glu
draw structure of urea
H₂N-C=O-NH₂
lec8, slide 25
Draw the urea cycle
lec 8, slide 26
Draw reaction of carbamoyl phosphate synthase I
2 ATP+ HCO3⁻ + NH3→ carbamoyl P + 2ADP + 2Pi
CPSII is involved in N.A metabolism
Rate limiting step for urea cycle?
Carbamoyl Phosphate Synthase I
Ornithine transcarboxylase
carbamoyl P + ornithine →
citruline
Mutations which reduce efficiency of urea cyle
Hyperamonemia
-lethargy
-retardation
✬Treat w/ Δ diet, NAG analogs, ↑Arg (→ornithine)
