Empirical Formula (Hill Notation): C10H16N5O14P3 · xNa+, Molecular Weight: 523.18 (free acid basis), ≥95% (HPLC), powder, Synonym: GTP. Guanosine 5′-triphosphate sodium salt hydrate has been used: in the preparation of horseradish peroxidase (HRP)-modified platination reagents, in whole cell, voltage-clamp recordings, and in in vitro inhibition of transglutaminase (tTG).