Interaction of Trypsin with Multilamellar Vesicles of Soybean Lipids

O. M. Martynova², O. P. Tiourina¹, A. A. Selischeva¹, G. M. Sorokoumova², V. I. Shvets², and N. I. Larionova^1*

¹School of Chemistry, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-5417; E-mail: nilar@enzyme.chem.msu.ru

²Lomonosov Academy of Fine Chemical Technology, pr. Vernadskogo 84, Moscow, 117571 Russia; fax: (095) 434-8233; E-mail: biotechnology@mtu-net.ru

^* To whom correspondence should be addressed.

Received December 30, 1999; Revision received February 1, 2000

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The pH dependence of complex formation of trypsin with multilamellar vesicles (MLV) of soybean lipids has been investigated. The lipids were characterized by the same phospholipid composition, but the content of other lipids differed. Decrease of pH or introduction of negatively charged components into the lipid samples increased trypsin content in the protein-lipid complexes. This suggests electrostatic interaction between the protein and soybean lipids. The dependence of trypsin activity in the complexes with MLV on their concentration and on the presence of an ionic detergent was studied. Trypsin-MLV interaction did not result in complete inactivation of the protein molecules. Moreover, the effects of dilution and addition of ionic detergent on trypsin activity were additive. Using a fluorescence technique, complex formation with MLV was found to stabilize trypsin molecules, preventing their autolysis.

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KEY WORDS: soybean phospholipids, multilamellar vesicles, trypsin, protein-lipid complexes, enzyme activity

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