Question

If changing the pH of an enzyme solution greatly reduces the activity of that enzyme without precipitation, how could you tell in the lab if the result of denaturation or just going to a pH that is just not a good one for the enzyme? And how would a change in pH impact or even stop enzyme function without denaturation? (consider the enzymes that are active in your stomach, such as pepsin)

Answer 1

Answer-

Denaturation of enzyme - It is the process which involves complete disruption of normal 3D structure of enzyme, as a result of which enzyme can't catalyse biological reactions normally.

Effect of pH changes on enzyme activity- Every enzyme functions best at a optimal pH range. Any pH condition either above and below that pH range greatly decreases the activity of enzyme.

Effect of pH changes on enzyme- The change of pH will lead to the ionization of amino acids atoms and molecules, change the shape and structure of proteins (sometimes these changes are so minor that the structure appears intact or we can say that these changes can occur without denaturation), thus damaging the function of proteins. Enzymes are also proteins, which are also affected by changes in pH. Many times when this effect (i.e., changes in shape) of pH doesn't leads to denaturation, then enzyme can restore its normal function when pH becomes normal. But a very drastic change in pH can lead to denaturation of enzyme, as a result of which enzyme can't resume it's normal functioning.

Pepsin is an endopeptidase released by chief cell of stomach which breaks down proteins into smaller amino acids. Pepsin exhibits maximal activity at pH 2.0 and is inactive at pH 6.5 and above, however pepsin is not fully denatured or irreversibly inactivated until pH 8.0.