Enzyme activity----how is it affected by temperature and pH?

Question

how is enzyme activty affect (and WHY) is it affected by temperature and pH level? Please reference :) Thanks.

Answer 1

Changes in temperature and pH change the three dimensional shape of the active site of the enzyme as well as the shape of the enzyme as a whole.  This change may render an enzyme ineffective.

Answer 2

somebody has a homework assignement and is feeling lazy!

enzymes only work at a certain pH and certain temperature.  they are rapidly inactivated and nonphysiological temp/pH

a good example is pepsin that is active in the stomach lumen at pH about 2.  then, when chyme passes into the duodenum (small bowel), the pH rises to 8 because of pancreatic OH and many different enzymes are active there (eg trypsin).  each enzyme is tailored to its unique pH.

at extremely unfavorable temp PH, enzymes can become denatured, meaning they lose their normal tertiary and quaternary structure.  obviously a misfolded or unfolded protein cannot have an enzymatic capacity.