Specificity of Diacylglycerol Acyltransferase from Bovine Mammary Gland, Liver and Adipose Tissue towards Acyl‐CoA Esters

Abstract

Microsomal diacylglycerol acyltransferase [EC 2.3.1.20] from bovine lactating mammary gland, liver and adipose tissue was capable of acylating microsomal-bound 1,2-dipalmitoylglycerol with acyl-CoA of chain length C4-C18. The activity of the liver and adipose enzymes towards butyryl-CoA and hexanoyl-CoA relative to longer-chain acyl-CoA was similar to that of the mammary enzyme. The Km and V values of the 3 enzymes with butyryl-CoA and hexanoyl-CoA were similar, but the V values of the adipose enzyme were higher. Microsomal diacylglycerol acyltransferase from mammary gland and liver of non-ruminants was also capable of utilizing butyryl-CoA. Apparently, the unique presence of short-chain acids in ruminant milk triacylglycerols is not caused by differences in specificity between the diacylglycerol acyltransferase from ruminant mammary and other tissues.