Protein kinases are enzymes that normally catalyze the degradation of cellular proteins.

a) synthesis of kinins.

b) phosphorylation of ADP.

c) phosphorylation of cellular proteins.

d) formation of peptide bonds in proteins.

c) phosphorylation of cellular proteins.

Explanation:

Background Knowledge:

Kinase Enzymes:

These are the enzyme which speedup the transfer of phosphate groups from high energy, phosphate-donating molecules like ATP to specific substrates. This process of phosphate donation from high energy molecules to specific substrate is known as phosphorylation.

Protein Kinases:

Protein kinases are the type of kinases which transfer phosphate group from high energy phosphate donating molecules to the proteins.

so correct answer of this question is c) phosphorylation of cellular proteins.