oxidation-reduction reactions involving the hydride ion (H-)
Vitamin B3
oxidation-reduction reactions involving two hydrogen atoms
vitamin B2
variety of reactions including the transfer of amino groups
Vitamin B6
intramolecular rearrangement reactions
Vitamin B12
carboxylation reactions
biotin
carrier of one-carbon units such as the formyl group
folic acid
carrier of acyl group
pantothenic acid
Enzyme inhibition divides into
Reversible Inhibition and Irreversible inhibition
Reversible inhibition breaks into
Competitive inhibition
then
Uncompetitive Inhibition
then
Non-competitive Inhibition
the inhibitors bind noncovalently to enzyme leading to rapid full inhibition
Reversible Inhibition
competition between the substrate and the inhibitor for the active site of an enzyme
Competitive Inhibition
inhibitor binds to the formed complex thus preventing the reaction of the enzyme with the substrate and the product formation
Uncompetitive Inhibition
Inhibitor binds to another site which is not the active site of the enzyme; allosteric site
Non-competitive inhibition
interferes with active sire of enzyme so substrate cannot bind
Competitive inhibitor
changes shape of enzyme so it cannot bind to substrate
Noncompetitive inhibitor
Nitric Oxide (NO) binds receptors in the smooth muscle cells of the penis. This results in increased levels of cyclic guanosine monophosphate (cGMP) which increases vasodilation. An enzyme called PDE5 (phosphodiesterase-5) degrades cGMP
Sildenafil (Viagra):
fits into the same active site of PDE5 as cGMP, thus competitively inhibiting PDE5 from working.
Sildenafil
Many antibiotic act as
allosteric inhibitors
acts by binding to the bacterial enzyme DD-transpeptidase.
Penicillin
Thebacteria uses this enzyme to catalyze the formation ofpeptidoglycann cross in its
cell wall