1Laboratory of Chemistry and Biophysics of Proteins and Enzymes, Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, 1113 Sofia, Acad. G. Bonchev Str., Block 9, Bulgaria.
2Institute of Technical Biocatalysis, Hamburg University of Technology, D-21073, Denickestr. 15, Hamburg, Germany.
*Corresponding author: E-mail: ktishinov@gmail.com
Online published 15 July, 2009.
The S’1 substrate specificity of the sunflower seed major aminopeptidase was studied with a series of dipeptide substrates with phenylalanine at P1 and a hydrophobic amino acid at P’1 position. The kinetic parameters of hydrolysis are significantly affected by the structure, side chain hydrophobicity and configuration of the P’1 moiety. Its binding during enzyme-substrate complex formation takes place at a hydrophobic site of limited size following an extraction mechanism as seen from the applied structure-activity correlation. Attempts to establish such dependencies for the catalytic step of the reaction reveal the presence of additional S’1 -P’1 enzyme-substrate interactions of greater complexity.
sunflower seed aminopeptidase, dipeptide hydrolysis, kinetic analysis, structure-activity correlation
