Purification and characterization of intracellular lipase from the polyunsaturated fatty acid-producing fungus Mortierella alliacea

N Biotechnol. 2011 Feb 28;28(2):158-64. doi: 10.1016/j.nbt.2010.09.007. Epub 2010 Oct 12.

Abstract

Previous studies on an arachidonic acid-producing fungus, Mortierella alliacea YN-15, suggested that its intracellular lipase plays an important role in the metabolism of exogenous and storage lipids. The lipase purified in this study through acetone precipitation and three-step chromatography was estimated to be about 11 kDa in size by SDS-PAGE and mass spectrometry, and it tended to form large aggregates in aqueous solution. The purified lipase retained its activity over wide ranges of pH (2-12) and temperature (20-80 °C). Its activity was enhanced by the Ca(2+) ion and reduced by some heavy metal ions, such as Zn(2+) and Hg(2+), and diethylpyrocarbonate. Among the various substrates tested, monoacylglycerols containing long-chain unsaturated fatty acids and phosphatidylcholine were preferentially hydrolyzed over triacylglycerols and fatty acid methyl esters. The lipase strongly hydrolyzed the sn-1/3 ester bonds and weakly hydrolyzed the sn-2 ester bonds of triolein, and it also catalyzed the acylglycerol synthesis reaction in a solvent-free two-phase system. The results indicate that triacylglycerol may be formed via 2-monoacylglycerol. Thus, the highly stable M. alliacea lipase may be useful for the synthesis of structured lipids, particularly acylglycerols containing functional unsaturated fatty acids at the sn-2 position.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Enzyme Stability
  • Fatty Acids, Unsaturated / chemistry
  • Fatty Acids, Unsaturated / metabolism*
  • Fungal Proteins / chemistry
  • Fungal Proteins / isolation & purification*
  • Fungal Proteins / metabolism
  • Lipase / chemistry
  • Lipase / isolation & purification*
  • Lipase / metabolism
  • Lipid Metabolism
  • Monoglycerides / chemistry
  • Monoglycerides / metabolism
  • Mortierella / chemistry
  • Mortierella / enzymology*
  • Phosphatidylcholines / metabolism
  • Substrate Specificity
  • Temperature
  • Triglycerides / chemistry
  • Triglycerides / metabolism

Substances

  • Fatty Acids, Unsaturated
  • Fungal Proteins
  • Monoglycerides
  • Phosphatidylcholines
  • Triglycerides
  • Lipase