Kinetic Properties of Acid Phosphatase

Introduction Phosphatases are enzymes that remove phosphate groups from substrates. Phosphorylated compounds are widely distributed in living systems. They serve as storage forms for energy (e.g., ATP and phosphocreatine), as components of informational macromolecules (i.e., nucleotides and deoxynucleotides), as allosteric effectors of certain enzymes (e.g., fructose-1-6bisphosphate), and as second messengers (e.g., cAMP, cGMP, inositol phosphates). Phosphorylation-dephosphorylation reactions of proteins, mediated by protein kinases and protein phosphatases, modulate many enzyme activities (phosphorylase, pyruvate dehydrogenase, etc.). It is therefore not surprising that phosphatases of many kinds can be extracted from many tissues. In general, these enzymes catalyze the hydrolysis of phosphate monoesters as follows: