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Improved stability and catalytic activity of chemically modified papain in aqueous organic solvents

Paper ID Volume ID Publish Year Pages File Format Full-Text
35233 45082 2009 6 PDF Available
Title
Improved stability and catalytic activity of chemically modified papain in aqueous organic solvents
Abstract

Papain was modified with the anhydrides of various monocarboxylic (acetic or propionic) and dicarboxylic (citraconic, maleic or succinic) acids. 7–10 of the 11 primary amino groups of the enzyme were modified. The organic solvent tolerances of the modified enzyme forms were increased (especially in the concentration range of 10–60%) in comparison with the unmodified enzyme. Acylation enhanced the catalytic activity and stability of papain both in buffer and in aqueous organic solvents (ethanol and acetonitrile). Decrease of the positive charges on the surface of papain resulted in a higher enzyme stability than when they were replaced by negative charges. The kinetic parameters revealed that in aqueous ethanol the maximum rates (Vmax) and Michaelis constants (KM) of the modified papain forms were increased, and higher catalytic efficiencies (kcat/KM) were detected as compared with the native enzyme. The results of near-UV circular dichroism and tryptophan fluorescence spectroscopic studies suggested that the modifications caused only local changes around the aromatic residues. The modified enzyme forms led to higher N-acetyl-l-tyrosine ethyl ester synthesis conversions in aqueous ethanol; acetyl and propionyl papain furnishing the highest productivity.

Keywords
Stability of papain; Chemical modification; Organic acid anhydrides; Organic solvents; Amino acid ester synthesis; CD and fluorescence spectroscopy
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Improved stability and catalytic activity of chemically modified papain in aqueous organic solvents
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 44, Issue 2, February 2009, Pages 199–204
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us