Fatty acid selectivity of a lipase purified from Vernonia galamensis seed

Research output: Contribution to journalArticle

Abstract

Vernonia galamensis is an annual herb whose seed oil contains high levels of an epoxy fatty acid, vernolic (cis-12,13-epoxy cis-9-octadecenoic) acid. The seed also contains lipase activity in the dormant state. A lipase was purified from the seed and its substrate specificity studied in isooctane. The lipase shows pronounced selectivity for the native triacylglycerol, trivernolin. The rate of hydrolysis of triolein, the corresponding non epoxy triacylglycerol, is only 3% of that of trivernolin. In the acidolysis of tricaprylin using a mixture of fatty acids, the Vernonia lipase also showed selectivity for vernolic acid. Michaelis-Menten kinetics of the hydrolysis of triacylglycerols revealed that the observed high selectivity of the Vernonia lipase for trivernolin was mainly due to a higher Vmax for trivernolin. The Vmax value for the hydrolysis of trivernolin was 5 times higher than that for triolein. This novel substrate specificity is an adaptation by the seed lipase to the triacylglycerols of the seed oil that contain up to 80% vernolic acid.

Details

Authors
Organisations
External organisations
  • Lund University
  • University of Zimbabwe
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biocatalysis and Enzyme Technology

Keywords

  • (V. galamensis), Fatty acid selectivity, Lipase, Purification
Original languageEnglish
Pages (from-to)149-156
Number of pages8
JournalBiochimica et Biophysica Acta - Lipids and Lipid Metabolism
Volume1257
Issue number2
Publication statusPublished - 1995 Jul 13
Publication categoryResearch
Peer-reviewedYes