luciferase

A bioluminescent enzyme isolated from light organs of fireflies. It catalyzes light emission (yellow-green, 560 nm) from luciferin after its activation by ATP and oxidative decarboxylation (by molecular oxygen). The quantum yield for this reaction is extremely high (0.88 photon/cycle). Under proper experimental conditions, the light output is proportional to the concentration of the limiting substrate (e.g., ATP). This makes the enzyme an exquisitely specific and sensitive (pM range) probe for detection and monitoring of ATP.
Normally located in peroxisomes, this 550 residues (62 kDa) protein can be redirected to various cellular locations by genetic engineering, and may serve as a probe for protein traffic and assembly, or as a powerful localized probe for local [ATP] in studies of organized metabolism to detect diffusion effects.
last update, Dec 1999 - Claude Aflalo - suggestions are welcome...