Phosphatase

A 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 (see dephosphorylation). This action is directly opposite to that of phosphorylases and kinases, which attach phosphate groups to their substrates by using energetic molecules like ATP. A common phosphatase in many organisms is alkaline phosphatase. Another large group of proteins present in archaea, bacteria, and eukaryote exhibits deoxyribonucleotide and ribonucleotide phosphatase or pyrophosphatase activities that catalyse the decomposition of dNTP/NTP into dNDP/NDP and a free phosphate ion or dNMP/NMP and a free pyrophosphate ion.^[1]^[2]^[3] The other group of phosphatase is collectively called as protein phosphatase, which removes a phosphate group from the phosphorylated amino acid residue of the substrate protein. Protein phosphorylation is a common posttranslational modification of protein catalyzed by protein kinases, and protein phosphatases reverse the effect.

References

↑ Davies O, Mendes P, Smallbone K, Malys N (2012). "Characterisation of multiple substrate-specific (d)ITP/(d)XTPase and modelling of deaminated purine nucleotide metabolism". BMB Reports. 45 (4): 259–64. doi:10.5483/BMBRep.2012.45.4.259. PMID 22531138.
↑ Martin, S. S.; Senior, H. E. (1980). "Membrane adenosine triphosphatase activities in rat pancreas". Biochim. Biophys. Acta. 602: 401–418. doi:10.1016/0005-2736(80)90320-x. PMID 6252965.
↑ Riley, M. V.; Peters, M. I. (1981). "The localization of the anion-sensitive ATPase activity in corneal endothelium". Biochim. Biophys. Acta. 644: 251–256. doi:10.1016/0005-2736(81)90382-5. PMID 6114746.

Phosphatases at the US National Library of Medicine Medical Subject Headings (MeSH)

3.1.1: Carboxylic
ester hydrolases

Endodeoxyribonuclease	Deoxyribonuclease I Deoxyribonuclease II Deoxyribonuclease IV Restriction enzyme UvrABC endonuclease

Endoribonuclease	RNase III RNase H 1 2A 2B 2C RNase P RNase A 1 2 3 4/5 RNase T1 RNA-induced silencing complex

either deoxy- or ribo-	Aspergillus nuclease S1 Micrococcal nuclease

Enzymes

Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Enzyme kinetics Lineweaver–Burk plot Michaelis–Menten kinetics

Regulation	Allosteric regulation Cooperativity Enzyme inhibitor

Classification	EC number Enzyme superfamily Enzyme family List of enzymes

Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list)

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