AP BIOLOGY

Detailed explanation-1: -Protein kinases Activation or deactivation of kinase occurs in different ways: through the kinase itself with a cis-phosphorylation/autophosphorylation, by binding with activator or inhibitor proteins or checking their localization in the cell in relation to their substrate (7).

Detailed explanation-2: -Phosphatase is an enzyme that removes a phosphate group from its substrate by hydrolysing phosphoric acid monoesters into a phosphate ion and a molecule with a free hydroxyl group.

Detailed explanation-3: -In fact protein kinases and phosphatases are both phosphotransferases, but in vivo their function is tightly regulated, phosphorylation is always catalysed by kinases whereas dephosphorylation is driven by phosphatases.

Detailed explanation-4: -Dephosphorylation of the three processing sites (activation loop, turn motif, hydrophobic motif) of PKC inactivates the kinase.