Reductive alkylation of lipase: experimental and molecular modeling approaches
Document Type
Article
Publication Date
1-1-2004
Abstract
Candida rugosa lipase was modified via reductive alkylation to increase its hydrophobicity to work better in organic solvents. The free amino group of lysines was alkylated using propionaldehyde with different degrees of modification obtained (49 and 86%). Far-ultraviolet circular dichroism (CD) spectroscopy of the lipase in aqueous solvent showed that such chemical modifications at the enzyme surface caused a loss in secondary and tertiary structure that is attributed to the enzyme unfolding. Using molecular modeling, we propose that in an aqueous environment the loss in protein structure of the modified lipase is owing to disruption of stabilizing salt bridges, particularly of surface lysines. Indeed, molecular modeling and simulation of a salt bridge formed by Lys-75 to Asp-79, in a nonpolar environment, suggests the adoption of a more flexible alkylated lysine that may explain higher lipase activity in organic solvents on alkylation.
Keywords
Candida rugosa, Circular dichroism, Enzyme modification, Lipase, Molecular modeling, aspartic acid, fungal enzyme, lysine, organic solvent, propionaldehyde, triacylglycerol lipase, alkylation, aqueous solution, chemical modification, conference paper, enzyme structure, hydrophobicity, molecular model, protein folding, protein structure, reduction, simulation, ultraviolet radiation, Candida, Hydrogen Bonding, Models, Molecular, Oxidation-Reduction, Transferases
Divisions
CHEMISTRY
Publication Title
Applied Biochemistry and Biotechnology - Part A Enzyme Engineering and Biotechnology
Volume
118
Issue
1-3
Additional Information
Department of Chemistry, Faculty of Science Building, University of Malaya, 50603 Kuala Lumpur, MALAYSIA