Tags: Enzyme.
In enzymology a guanosine-triphosphate guanylyltransferase (EC 2.7.7.45) is an enzyme that catalyzes the chemical reaction2 GTP diphosphate + P1P4-bis(5′-guanosyl) tetraphosphateHence this enzyme has one substrate GTP and two products diphosphate and P1P4-bis(5′-guanosyl) tetraphosphate.This enzyme belongs to the family of transferases specifically those transferring phosphorus-containing nucleotide groups (nucleotidyltransferases).