GTPHydrolyse

GTPhydrolyse is the biochemical process by which guanosine triphosphate (GTP) is hydrolyzed to guanosine diphosphate (GDP) and inorganic phosphate (Pi). The term is sometimes used as a general label for the hydrolysis step within GTPase-driven signaling cycles, rather than as a reference to a specific enzyme. In most cells, GTPhydrolyse is carried out by GTPases and related hydrolases.

The reaction is typically facilitated by an active-site water molecule acting as a nucleophile, aided by catalytic residues and, in many cases, a bound Mg2+ ion that stabilizes the transition state. The process results in a conformational change of the GTPase, enabling downstream effects such as assembly/disassembly of protein complexes or switching between active and inactive states.

Biological roles: GTPhydrolyse is central to energy transduction and signal transduction; examples include Ras-family GTPases controlling cell growth, or EF-Tu in translation elongation. The hydrolysis step often serves as a timing mechanism that couples to GDP exchange and effector binding.

Regulatory factors: GAPs accelerate hydrolysis, while GEFs promote nucleotide exchange to reinitiate signaling cycles. The rates can be influenced by cellular conditions and post-translational modifications.

Clinical and research relevance: Abnormal GTPhydrolyse activity is implicated in cancer, developmental disorders, and bacterial pathogenesis when signaling timeliness is perturbed.

Terminology and history: The name GTPhydrolyse derives from older nomenclature and is less commonly used in contemporary literature, where "GTPase activity" or "GTP hydrolysis" are standard terms. The concept remains central to understanding how cells convert chemical energy stored in GTP into regulated structural and signaling changes.