Question

1. do all enzymes have the same active site? why ?

2. What is meant by the optimal temperature and the optimal pH for an enzyme? What biological significance do these parameters have?

Answer 1

1.

Active site of an enzyme which binds to ligand. Every enzyme is specific for a particular ligand. The shape of ligand and active site of enzyme are complementary to each other and the ligand fits into the active site like a key fits into a lock. This interaction between ligand and active site occurs due to interaction between amino acids present on the active site and those present on the ligand. Any change in the amino acids in either active site of enzyme or in the ligand or both leads to alteration of interaction between the two and therefore the ligand cannot bind to active site properly.

After reading the above information, you may be able to make out that enzyme ligand interaction is very specific. Therefore, every enzyme has a different set of amino acids on its active site and a different shape so that a particular ligand can bind to it only.

2.

Every protein works at a range of temperature and pH. This range is called as optimum temperature and optimum pH. Any increase or decrease in this optimum value is detrimental for the structure of proteins and therefore their function. We know that all enzymes are proteins in nature. Therefore all enzymes work at an optimum temperature and pH. Any increase or decrease in this value results in loss of catalytic activity of enzymes.

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