Absence of Fatty Acid Specificity During Lipolysis of Some Synthetic Triglycerides by B-Esterase Preparations from Milk

Summary The specificity of B-esterase preparations from bovine milk for short-chain fatty acids was studied by using as substrates glyceryl 1-oleate 2,3-dicaproate (OCC) and glyceryl 1-palmitate 2,3-dibutyrate (PBB). These triglycerides were emulsified into skimmilk, incubated with the B-esterase preparations for varying lengths of time at 38C, and the products of lipolysis isolated by column and thin-layer chromatography. The fatty acid compositions of the isolated free fatty acids and mono- and diglycerides were determined by gas-liquid chromatography. Absence of specificity for short-chain acids was indicated by the release of equimolar quantities of caproate and oleate or butyrate and palmitate during lipolysis periods of up to 1 hr. When PBB was incubated at 4C for 24 hr, there was apparent specificity for butyrate which was probably caused by the comparatively rapid lipolysis of dibutyrin in contrast to glyceryl 1-palmitate 2-butyrate at the diglyceride stage.