Measuring stereoselectivity in lipase‐catalyzed acidolysis reactions by ultra‐high resolution ¹³C nuclear magnetic resonance

Abstract

Elucidating the stereoselectivity of lipases in synthetic reactions of triacylglycerols has hitherto been carried out using traditional analytical techniques to determine the composition of the reaction products. These methods are laborious and are not always appropriate for analysis of certain triacylglycerol types. A direct method, utilizing a stereospecific deuteriumlabeled triacylglycerol substrate, has been developed where the stereoisomeric composition of the reaction product is determined by ultra-high resolution 13 C nuclear magnetic resonance (NMR) spectroscopy. Through lipase-catalyzed transesterification of deuterium-labeled trilauroylglycerol with oleic acid, chemical shifts were induced in the 13 C NMR spectrum by the deuterium atom and olefinic double bonds, enabling unambiguous stereospecific assignment of triacylglycerol species. By this method of analysis, we found an effect of the degree of reaction conversion on the extent of stereoisomerism in the triacylglycerol product. Stereoselectivity was greatest (for sn-1) with lipase from Rhizomucor miehei. Lipases from Rhizopus niveus, Candida rugosa, Carica papaya, and the cutinase from Fusarium sp. were also found to exhibit stereoselectivity, with preference for either sn-1 or sn-3 acyl exchange.Paper no. J9811 in JAOCS 78, 953-958 (September 2001).

A process for the production of a diacylglycerol‐based milk fat analogue

“…4, and for the same reasons, also RM and to a lesser extent TL seemed to show either longchain or stereospecificity for the sn-1 positions. sn-1 stereospecificity of RM and TL lipases is reported in the literature [24,25].…”

Bacterial lipase triggers the release of antibiotics from digestible liquid crystal nanoparticles

“…Despite similarities in the extent of MO-LCNP digestion from the model lipases explored in the present study, Pseudomonas lipase displayed different digestion kinetics to pancreatic lipase. This is explained by the sn-1 and 3 regiospecificity of pancreatic lipase [43,73], which produced more 2-monoglycerides (2-MG) as the major lipolytic product of the 1, 2-diglycerides in the Myverol 18-99K mixture. In comparison, the Pseudomonas lipases had no regiospecificity and a larger proportion of 1-monoglycerides (1-MG) was present in the products, which would eventually be consumed, as represented in Figure 12.…”

Lipase‐catalyzed interesterification reactions for human milk fat substitutes production: A review

“…However, these methods are more reliable and time‐consuming. To overcome such drawbacks, other very powerful techniques such as 13 C NMR spectroscopy or ultra‐high resolution NMR have been successfully employed 103, 104. Recently, a MS ionization technique in tandem with HPLC (HPLC–MS) was developed to analyze TAGs in complex matrices, such as milk fat or HMF without prior separation 105.…”