title: Enzymatic synthesis of γ-L-glutamyl-S-allyl-L-cysteine, a naturally occurring organosulfur compound from garlic, by Bacillus licheniformis γ-glutamyltranspeptidase.
abstract: 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.
authors.affiliation: Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City 60004, Taiwan.
authors.forename: Yi-Yu
authors.initials: YY
authors.lastname: Chen
authors.affiliation: Department of Food Science and Technology, Hungkuang University, 1018 Taiwan Boulevard, Shalu District, Taichung City 43302, Taiwan.
authors.forename: Huei-Fen
authors.initials: HF
authors.lastname: Lo
authors.affiliation: Department of Chemistry, National Cheng Kung University, Tainan City 701, Taiwan.
authors.forename: Tzu-Fan
authors.initials: TF
authors.lastname: Wang
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei City 11529, Taiwan.
authors.forename: Min-Guan
authors.initials: MG
authors.lastname: Lin
authors.affiliation: Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City 60004, Taiwan. Electronic address: llin@mail.ncyu.edu.tw.
authors.forename: Long-Liu
authors.initials: LL
authors.lastname: Lin
authors.affiliation: Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi City 60004, Taiwan. Electronic address: s0910324@mail.ncyu.edu.tw.
authors.forename: Meng-Chun
authors.initials: MC
authors.lastname: Chi
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000378:metabolism; D003545:Cysteine / Q000031:analogs & derivatives / Q000378:metabolism; D004151:Dipeptides / Q000096:biosynthesis* / Q000302:isolation & purification; D004800:Enzymes, Immobilized / Q000378:metabolism; D005737:Garlic / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D011994:Recombinant Proteins / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization; D013457:Sulfur Compounds / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D013696:Temperature; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004151:Dipeptides; D004800:Enzymes, Immobilized; D011994:Recombinant Proteins; D013457:Sulfur Compounds; C000603974:gamma-glutamyl-S-allylcysteine; D005973:Glutamine; C065299:S-allylcysteine; D005723:gamma-Glutamyltransferase; D003545:Cysteine
keywords: Bacillus licheniformis; Biocatalyzed synthesis; Organosulfur compound; γ-Glutamyltranspeptidase; γ-L-Glutamyl-S-allyl-L-cysteine