Answer to Question #176141 in Biochemistry for linta

Question

Carbonic anhydrase is strongly inhibited by the drug acetazolamide, which is used as a diuretic. Carbonic anhydrase plays a significant role in the secretary processes because it participates in regulating the pH and bicarbonate of body fluids. The experimental curve of initial reaction velocity versus [S] for the carbonic anhydrase is shown below. When the experiment is repeated in the presence of acetazolamide, the lower curve is obtained. Determine the nature of inhibition. Explain with reason.

Answer 1

$\bigstar$ The graph is shown below

for no inhibitor and for Acetazolamide

Initial reaction velocity versus [S] for the carbonic anhydrase

$\implies$ In the experiment we got.......

$\bigstar$ The inihibitation of the carbonic anhydrase catalyzed by hydration of caron diaoxide by acetazolamide or can be done by benzthiazide.

$\bigstar$ After equilibrium of drug with enzyme at 5$\degree$ C and pH 8.0 in the absence of substrate.

$\bigstar$ Acetazolamide rapidly comes to equilibrium with the enzyme under these conditions with small increase in potency .

$\bigstar$ This increase is greatly diminished when substrate is present.

$\bigstar$ The K$_i$ of acetazolamide is under these conditions 8.5$\times$ 10$^{-8}$ M.

$\bigstar$ The combination of acetazolamide with the enzyme is freely reversible .

$\implies$ Note That

{some properties of Acetazolamide are }

$\bull$ Acetazolamide is Sulfonamide derivative with diuritic , antiglaucoma and anticonvulsant properties.

$\bull$ Acetazolamide isnon-competitive inhibitor of carbonic anhydrase.

These are the reasons for which lower curve is obtained for acetazolamide presence .