GTPase-activating proteins
GTPase-activating proteins , abbreviated to GAP (“GTPase-activating proteins”), are proteins that act on G-proteins in such a way that they hydrolyse their bound GTP by splitting off a phosphate residue to form GDP . In most cases this deactivates the target protein, since it is only active in the GTP-bound form. The G proteins themselves are GTPases . As the name suggests, the GAPs only speed up the process of GTP hydrolysis, and the reaction would take place even without the GAPs. However, for most processes in the cell it is important that the activated G proteins are switched off again quickly. The faster the "turnover", the faster changes can become noticeable.
The GAPs are the antagonists of the GTP Exchange Factors (GEFs), which have exactly the opposite effect.
Individual evidence
- ↑ GTPase-activating proteins . In: Lexicon of Biochemistry. Spectrum Academic Publishing House, Heidelberg, 1999.
literature
- B. Alberts et al. (2002): Molecular Biology of the Cell