Accepted name: mRNA 5′-phosphatase
Reaction: a 5′-triphospho-[mRNA] + H2O = a 5′-diphospho-[mRNA] + phosphate
Other name(s): 5′-polynucleotidase; polynucleotide 5′-phosphohydrolase; RNGTT (gene name); CET1 (gene name); mRNA 5′-triphosphate monophosphatase
Systematic name: 5′-triphospho-mRNA 5′-phosphohydrolase
Comments: The enzyme, found in eukaryotes and some plus strand RNA viruses (e.g. alphavirus), is involved in mRNA capping. Unlike the eukaryotic enzyme, the viral enzyme requires a purine in the first position of the mRNA. The human enzyme is a multi domain protein that also has the activity of EC, mRNA guanylyltransferase.
1.  Itoh, N., Mizumoto, K. and Kaziro, Y. Messenger RNA guanlyltransferase from Saccharomyces cerevisiae. II. Catalytic properties. J. Biol. Chem. 259 (1984) 13930–13936. [PMID: 6094533]
2.  Tsukamoto, T., Shibagaki, Y., Murakoshi, T., Suzuki, M., Nakamura, A., Gotoh, H. and Mizumoto, K. Cloning and characterization of two human cDNAs encoding the mRNA capping enzyme. Biochem. Biophys. Res. Commun. 243 (1998) 101–108. [PMID: 9473487]
3.  Vasiljeva, L., Merits, A., Auvinen, P. and Kaariainen, L. Identification of a novel function of the alphavirus capping apparatus. RNA 5′-triphosphatase activity of Nsp2. J. Biol. Chem. 275 (2000) 17281–17287. [PMID: 10748213]
[EC created 2021]