Escherichia coli diacylglycerol kinase is an evolutionarily optimized membrane enzyme and catalyzes direct phosphoryl transfer

Abstract

In this contribution the kinetic mechanism and substrate specificity of Escherichia coli diacylglycerol kinase were examined. Steady state kinetic studies were carried out under mixed micellar conditions using a novel continuous coupled assay system. The kinetic data were consistent with a random equilibrium mechanism, implying that diacylglycerol kinase catalyzes direct phosphoryl transfer from MgATP to diacylglycerol. This was supported by failure to detect an enzyme-phosphate covalent intermediate and by the observation that the bisubstrate analog adenosine 5'-tetraphosphoryl-3-O- (1,2-dihexanoyl)-sn-glycerol inhibits the enzyme (K(i)