mRNA guanylyltransferase

In enzymology, a mRNA guanylyltransferase (EC 2.7.7.50) is an enzyme that catalyzes the chemical reaction

GTP + (5')ppPur-mRNA ${\displaystyle \rightleftharpoons }$diphosphate + G(5')pppPur-mRNA

Thus, the two substrates of this enzyme are GTP and (5')ppPur-mRNA, whereas its two products are diphosphate and G(5')pppPur-mRNA.

This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing nucleotide groups (nucleotidyltransferases).op The systematic name of this enzyme class is GTP:mRNA guanylyltransferase. Other names in common use include mRNA capping enzyme, messenger RNA guanylyltransferase, and Protein 2.

As of late 2007, 5 structures have been solved for this class of enzymes, with PDB accession codes 1CKM, 1CKN, 1CKO, 1P16, and 2C46.

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• Martin SA, Moss B (1975). "Modification of RNA by mRNA guanylyltransferase and mRNA (guanine-7-)methyltransferase from vaccinia virions". J. Biol. Chem. 250 (24): 9330–5. doi:10.1016/S0021-9258(19)40647-9. PMID 1194287.
• Martin SA, Paoletti E, Moss B (1975). "Purification of mRNA guanylyltransferase and mRNA (guanine-7-) methyltransferase from vaccinia virions". J. Biol. Chem. 250 (24): 9322–9. doi:10.1016/S0021-9258(19)40646-7. PMID 1194286.