ubiquitiiniaktivaasi
Ubiquitiniaktivaasi, also known as E1 enzyme, is a critical component of the ubiquitination pathway in eukaryotic cells. This enzyme is responsible for the initial step in the conjugation of ubiquitin, a small regulatory protein, to target proteins. The process begins with the activation of ubiquitin itself. Ubiquitiniaktivaasi binds to ATP and then to a molecule of ubiquitin. Through a series of reactions involving adenylation and thiolester formation, the carboxyl-terminus of ubiquitin is covalently attached to a cysteine residue on the ubiquitiniaktivaasi. This activated ubiquitin is now primed for transfer to the next enzyme in the cascade, the ubiquitinekonjugating enzyme (E2).
There are typically a limited number of ubiquitiniaktivaasi enzymes in a cell, reflecting their crucial and