Identification of lysophosphatidic acid acyltransferase in the microsomal membranes of developing castor endosperm

摘要

A photoreactive substrate analog of acyl-CoA, 12-[(4-azidosalicyl)amino] dodecanoyl-CoA (ASD-CoA) acts as a competitive inhibitor of acyl-CoA: lysophosphatidic acid acyltransferase in the microsomal membranes of developing castor endosperm (Ricinus communis L.). The acyltransferase was irreversibly inactivated when the microsomal membranes were exposed to ultraviolet light in the presence of ASD-CoA. The substrate, oleoyl-CoA was able to protect the enzyme against photoinactivation. Analysis by SDS-PAGE followed by autoradiography of microsomal membrane photolysed with ~(125)I-labelled ASD-CoA revealed major labelling of a single protein with the molecular mass of 29 kDa, suggesting that this protein could be the putative LPA acyltransferase.