Competitive Inhibition Flashcards
Inhibitor is a ———— of the substrate
Structural analog
Why is the reaction velocity reduced
Because
Half enzyme molecules are trapped but Inhibitor
Half molecules are available for catalysis to form product
Thus effective concentration of enzyme is reduced
An example of competitive inhibition is
Substrate succinate
Inhibitor malonate
Enzyme succinate dehydrogenase
Competitive inhibition is reversible or irreversible
Reversible
How can it be reversed
Excessive substrate concentration
Km ———— in présence of competitive inhibitor
Increases
Vmax is not changed
Why
Because on increasing substrate concentration it can be reversed
Allopurinol inhibits enzyme
Xanthine oxidase
Clinical use of allopurinol
Gout
Substrate allopurinol acts on
Hypoxanthine
Xanthine
Lovastatin inhibits ———
HMGCoA reductase
Substrate of lovastatin is
HMG CoA
Clinical use of HMG CoA
Cholesterol lowering
Bacteria synthesize folic acid by combining PABA with pteroyl glutamic acid in presence of enzyme
Pteroid synthétase
——— being structural analog of PABA will inhibit folic acid synthesis in bacteria
Sulfonamides
What is methotrexate
4 amino N10 methyl folic acid
Methotrexate inhibits this enzyme
Dihydrofolate Reductase
Methotrexate inhibits cell division and DNA synthesis so it’s used as
Anti cancer drug
Dicoumarol is structurally similar to
Vit K
Dicoumarol acts as an
Anticoagulant
Dicoumarol inhibits
Vit k epoxide reductase
Isonicotinic anhydride is used as ———- drug
Antituberculous
INH is similar to ———
Thus prolonged use of INH results in peripheral neuropathy
Pyridoxal
———— is used for methanol poisoning
Ethanol