Which enzyme hydrolyzes GTP into GDP and Pi?

The enzyme that hydrolyzes GTP into GDP and inorganic phosphate (Pi) is GTPase. GTPases belong to a large family of enzymes that play crucial roles in cellular signaling processes. They catalyze the hydrolysis of guanosine triphosphate (GTP) to guanosine diphosphate (GDP), releasing a phosphate group in the process. This reaction is vital for controlling various cellular functions, including signal transduction pathways and protein synthesis, as the transition between GTP-bound active state and GDP-bound inactive state regulates the activity of GTPase proteins.

In contrast, kinases are enzymes that typically transfer a phosphate group from ATP to a substrate, while phosphatases remove phosphate groups from molecules. Ligases, on the other hand, are enzymes that facilitate the joining of two substrates, often forming a new chemical bond. Understanding the specific role of GTPases is important for grasping the mechanics of molecular signaling and regulation in biological systems.