Question

QUESTION 17

1. Insulin and chymotrypsin are both activated by:

   		Ca2+
   		ATP
   		Proteolytic activation
   		AMP kinase cascade

Answer 1

Every active protein is present in an inactive form in the earlier stages and gets activated by some of the mechanisms such as Ca2+ ion concentration changes or any other allosteric regulation. But, some protein is activated by the proteolytic cleavage that means some of the parts (peptide bonds) of the whole protein are removed out by cleaving it and turning the protein into the active form. Thus in the case of the insulin, the inactive forms are of two type that are pre insulin and proinsulin. In the case of pre-insulin, some of the inhibitory peptides which are not allowing the functioning of the insulin are present and they are removed by the proteolytic cleavage. Similarly in the pro-insulin part which again cleaved to give rise to the active form of insulin.

However, the similar case goes with the chymotrypsin which is activated by the action of trypsin over it by cleavage of the peptide bond between arginine and isoleucine are cleaved by hydrolyzing it and then the further modification in the folding of protein will occur in such a way that the inactive form of the chymotrypsin will be changed into the active form and that too by the proteolytic cleavage action.

Thus the answer for the question is Insulin and Chymotgrypsin both are activated by proteolytic cleavage.