1- Fundamentals Of Biochem Flashcards
Cofactors
Metal ions, essential trace elements, interact with enzyme via noncovalent interaction, stabilize active site
Coenzymes
Small organic molecules, derived from vitamins
Cytochrome c oxidase
Cu COFACTOR
Accepts electrons from cytochrome-c in the electron transport chain
Superoxide dimutase
Cu COFACTOR
Antioxidant
Binds the free radical of molecular oxygen
Heme proteins (hemoglobin and myoglobin)
Fe COFACTOR
- require FE2+ to bind O2
ATPases
Mg COFACTOR
Hydrolyze ATP to ADP and use the released energy to do mechanical work like transport ions
Gluthanthione peroxidase
Se COFACTOR
Antioxidant, detoxifies hydrogen peroxide
Superoxide dismutase
Zn COFACTOR
(Antioxidant)
Binds the free radical of molecular oxygen
Coenzyme 2 subdivisions
1) co-substrate: temporary association (bind then detach in altered state)
- I.e. NAD+
2) prosthetic: permanent association
- I.e. Heme, FAD
Carbonic anhydrase
Zn COFACTOR
inter converts CO2 and bicarbonate to balance blood pH
competitive inhibition
Vmax no change
Km increases
- compete for binding site with substrate
noncompetitive inhibition
Vmax decrease
Km increases
- binds to E and ES complex, at site other than substrate active site
uncompetitive inhibition
Vmax decreases
Km decreases (by same factor//parallel line)
-only binds to ED complex at site other than substrate binding site
allosteric enzymes
- activity modulated by noncovalent binding of a metabolite to a site other than the catalytic site
- affects substrate by inducing conformational changes with binding
- can be POSITIVE (activators) or NEGATIVE (inhibitors) effectors
isozyme and example
same catalytic function, different primary sequence
Example: markers of MI: Troponin cTn-1
