HMP shunt flash Flashcards
Questions
Answers
Alcohol DH
ADH. Ethanol–> Acetaldehyde + NADH
Aldehyde DH
ALDH. Acetaldehyde –> acetate + NADH
Acetaldehyde
Accumulation leads to symptoms of hangovers, treat alcoholics with ALDH inhibitor
HMP oxidative pathway
Generate NADPH
HMP non-oxidative pathway
Convert 5 carbons sugars to 6
Transketolase
Requires thiamine pyrophosphate. In HMP: X5P or R5P–> G3P or Se-7P
Transaldolase
Forms covalent bond by using amino group of Lys as nucleophile. Se-7P + G3P –> E4P+F6P
G6P DH
G6P–>6-Phosphogluconolactone + NADPH. Irreversible. High NADP+ activates
6 Phosphogluconoate DH
6-phosphogluconolactate –> Ribulose-5P + NADPH
Glutathione
Membrane bound in RBC. Structure: glu-cys-glu. GSH is reduced state, when oxidized it forms GS-SG (protects membrane lipids and proteins from oxidation). GS-SG is then reduced by NADPH
Glutathione reductase
Enzyme that reduces oxidized glutathione. Uses NADPH
Oxidase
Enzyme that transfers electrons to oxygen to make water or H2O2
Cytochrome P450
Mono-oxygenase enzyme (incorporate 1 atom of oxygen into substrate, other atom into water). First line of defense against many toxins, requires NADPH. Ethanol inhibits and other compounds (Ex. Tylenol) cannot be metabolized
Barbiturates
Sleeping pills metabolized by P450 system
Superoxide (O2-)
Made in mitochondria CoQ (eith e-) + O2 –> CoQ + O2- (occurs when O2 levels are high).
Superoxide dismutase
2 O2- + 2 H+ –> H2O2 + O2, mitochondrial enzyme. Main defense against superoxide
Catalase
2 H2O2–>2 H2O + O2 in peroxisomes, neutrophils, and mitochondria
Glutathione peroxidase
H2O2 + 2 GSH –> GSSG + 2 H2O. In mitochondria and RBC (cyto.)
