MeSH note : catalyzes the hydrolysis of guanosine 5'-triphosphate, 3'-diphosphate to yield guanosine
5'-diphosphate, 3'-diphosphate & orthophosphate; from E coli; also hydrolyzes other
guanosine 5'-triphosphate derivatives with at least one unsubstituted phosphate group
on the 3'-position, but not GTP, ATP or adenosine 5'-triphosphate, 3'-diphosphate;