Description
Cold-tolerant bacterial esterases and lipases have the unusual property of a flexible structure which allows these enzymes to accommodate a broad range of substrates and to be more solvent tolerant. These properties coupled with the stereoselectivity of enzymes, make esterases and lipases ideal catalysts for the chemical modification of pharmacophore molecules. Employing an array of techniques to identify esterase/lipase activity for industrial processes, an in-house microbial collection of psychrophilic microbes was used to screen for specific esterase/lipase activities. Two marine bacteria yielded esterase/lipase genes encoding LypA (V. cholera) and VlpA (artic-derived Vibro sp.). These enzymes have broad spectrum substrate activity and VlpA exhibits tolerance to solvents by retaining its catalytic activity in buffer-solvent mixtures.
The graph below shows the solvent tolerance of VlpA in di-methyl-sulfoxide (DMSO). VlpA (2 units) was reacted with 100µmoles p- nitrophenyl butyrate in 50mM Tris-Cl pH 9.0 in the presence of different amounts of DMSO. The initial reaction rates were measured and the percent activity relative to the “no solvent” control calculated. VlpA exhibits tolerance to the solvent by retaining its catalytic activity in buffer- solvent mixtures.
