STEADY-STATE KINETICS OF THE GLUTAMATE-DEHYDROGENASE FROM AN ARCHAEBACTERIAL EXTREME THERMOPHILE, ISOLATE AN1

A steady state kinetic study was carried out with the glutamate dehydr ogenase from the thermophilic, archaebacterial isolate AN1. Initial ve locity studies of the oxidative deamination reaction showed the mechan ism is sequential and indicated that the order of substrate addition i s random, while inhibition studies with products and substrate analogu es suggested a strong preference for NADP(+) to bind first. Initial ve locity studies of the reductive amination reaction showed that the mec hanism is sequential and indicated that the order of substrate additio n is random, while product inhibition studies and the effect of substr ate saturation on the initial velocity suggested that the preferred or der of substrate addition is NADPH, 2-ketoglutarate, ammonia.