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Enzymatic synthesis of γ-l-glutamyl-S-allyl-l-cysteine, a naturally occurring organosulfur compound from garlic, by Bacillus licheniformis γ-glutamyltranspeptidase

Paper ID Volume ID Publish Year Pages File Format Full-Text
16975 42628 2015 7 PDF Available
Title
Enzymatic synthesis of γ-l-glutamyl-S-allyl-l-cysteine, a naturally occurring organosulfur compound from garlic, by Bacillus licheniformis γ-glutamyltranspeptidase
Abstract

•γ-Glutamyltranspeptidase was employed for the synthesis of γ-L-glutamyl-S-allyl-L-cysteine (GSAC).•Glutamine and S-allyl-L-cysteine were used as the γ-glutamyl donor and acceptor, respectively.•The target product was quantitatively determined by TLC and computer-assisted image analysis.•The GSAC yield for the free and immobilized enzymes reached 19.3% and 18.3%, respectively.

In the practical application of Bacillus licheniformis γ-glutamyltranspeptidase (BlGGT), we describe a straightforward enzymatic synthesis of γ-L-glutamyl-S-allyl-L-cysteine (GSAC), a naturally occurring organosulfur compound found in garlic, based on a transpeptidation reaction involving glutamine as the γ-glutamyl donor and S-allyl-L-cysteine as the acceptor. With the help of thin layer chromatography technique and computer-assisted image analysis, we performed the quantitative determination of GSAC. The optimum conditions for a biocatalyzed synthesis of GSAC were 200 mM glutamine, 200 mM S-allyl-L-cysteine, 50 mM Tris–HCl buffer (pH 9.0), and BlGGT at a final concentration of 1.0 U/mL. After a 15-h incubation of the reaction mixture at 60 °C, the GSAC yield for the free and immobilized enzymes was 19.3% and 18.3%, respectively. The enzymatic synthesis of GSAC was repeated under optimal conditions at 1-mmol preparative level. The reaction products together with the commercially available GSAC were further subjected to an ESI-MS/MS analysis. A significant signal with m/z of 291.1 and the protonated fragments at m/z of 73.0, 130.1, 145.0, and 162.1 were observed in the positive ESI-MS/MS spectrum, which is consistent with those of the standard compound. These results confirm the successful synthesis of GSAC from glutamine and S-allyl-L-cysteine by BlGGT.

Keywords
γ-Glutamyltranspeptidase; Bacillus licheniformis; Biocatalyzed synthesis; Organosulfur compound; γ-L-Glutamyl-S-allyl-L-cysteine
First Page Preview
Enzymatic synthesis of γ-l-glutamyl-S-allyl-l-cysteine, a naturally occurring organosulfur compound from garlic, by Bacillus licheniformis γ-glutamyltranspeptidase
Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volumes 75–76, July–August 2015, Pages 18–24
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering