Phosphate-handling enzymes





Transfer of phosphate group from an inorganic phosphate to an acceptor (usually a sugar).

Bacterial phosphorylases employ the same catalytic mechanisms as their plant and animal counterparts, but differ considerably in terms of their substrate specificity and regulation. That is, catalytic domains are highly conserved, while the regulatory sites are only poorly conserved. [s][r]

glycogen phosphorylase

Protein kinases

Transfer a phosphate group from a donor such as ATP to amino acid acceptors in proteins.

Serve important roles in signal transduction.

protein kinase A, protein kinase C, protein tyrosine kinases (PTKs), cAMP-dependent protein kinase (AKAPs), MAP Kinase, receptor tyrosine kinases, (RTKs), Table RTKs, w Ca2+/calmodulin-dependent protein kinases, w Mos/Raf kinases, w Protein Kinase B, w Receptor-associated tyrosine kinases, w Histidine-specific protein kinases, w Aspartic acid/glutamic acid-specific protein kinases


Remove, from amino acids, the phosphate groups attached by protein kinases.

Serve important roles in signal transduction.

PP1 (α, β, γ1, γ2), PP2A, w calcineurin (PP2B), PP2C, PP4, PP5

tyrosine phosphatases (CD45)

Adenylyl (adenylate) cyclases

Convert ATP to the second-messenger cAMP plus pyrophosphate.

Serve important roles in eukaryotic signal transduction.

Phospholipases, (phospholipases)

Hydrolyze specific ester bonds in phosphoglycerides or glycerophosphatidates, converting the phospholipids into fatty acids and other lipophilic substances.

Participate in transmission of ligand-receptor induced signals from the plasma membrane to intracellular proteins, primarily protein kinase C (PKC), which is maximally active in presence of Ca2+ and diacylglycerol.


w Phospholipase A (PLA), w Phospholipase B (PLB), w Phospholipase C (PLC), Phospholipase D (PLD)


Catalyze the hydrolysis of phosphodiester bonds, and so degrade the cyclic nucleotides, second messengers cAMP and cGDP to 5'-nucleotide monophosphates (AMP, GMP)

Important in regulation of signal transduction.

Enzymes of 10 identified phosphodiesterase families exist as homodimers with structural similarity, but differences with respect to selectivity for cyclic nucleotides, sensitivity for inhibitors and activators, physiological roles and tissue distribution.
DNA ligases DNA ligase forms covalent phospodiester bonds between 3'-OH of one nucleotide and 5'-PO4 of another.

DNA ligases are important research tools in recombinant DNA technology.

3'-phospodiesterase is important in repair of oxidative DNA damage.

DNA ligases I, II, III, IV

 Cell signaling  Receptor Tyrosine Kinases(RTK)  Second Messengers  Phosphate-handling Enzymes 

· adenylyl (adenylate) cyclase · cAMP-dependent protein kinase · CDKs · cyclin-dependent kinases · DAG · diacylglycerol · DNA ligases · ERKs · GPCRs · GPCR families · guanyl cyclase · inositol triphosphate · IP3 · MAP kinases · mitogen activated protein kinases · phosphatases · phosphodiesterases · phospolipases · phosphorylation · PKA · PKC · phospholipase C-gamma · protein kinase A · protein kinase C · protein tyrosine kinases (PTKs) · receptor tyrosine kinases · second messengers · signal transduction · two-component systems ·


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