AP BIOLOGY

Detailed explanation-1: -Protein kinases (PTKs) are enzymes that regulate the biological activity of proteins by phosphorylation of specific amino acids with ATP as the source of phosphate, thereby inducing a conformational change from an inactive to an active form of the protein.

Detailed explanation-2: -Protein kinases and phosphatases are enzymes catalysing the transfer of phosphate between their substrates. A protein kinase catalyses the transfer of -phosphate from ATP (or GTP) to its protein substrates while a protein phosphatase catalyses the transfer of the phosphate from a phosphoprotein to a water molecule.

Detailed explanation-3: -The protein kinases belong to the great family of kinases and are responsible for the mechanism of phosphorylation. They are activated by phosphorylation which in turn activates a cascade of events leading to the phosphorylation of different amino acids (3).

Detailed explanation-4: -A family of enzymes called kinases adds phosphate groups to a protein substrate. Kinases phosphorylate their targets by transferring the terminal phosphate group of ATP (or GTP) to its substrate. Protein kinases belong to an extensive family of enzymes that share a catalytic domain of 290 amino acids.

Detailed explanation-5: -The addition of a phosphate (PO43 −) group is often used as a major homeostatic control. In many proteins and enzymes, phosphorylation serves as a type of ‘on/off’ switch, thereby altering function or activity. Enzymes designated as kinases usually catalyze phosphorylation reactions using ATP as a cosubstrate.