title: Peptide synthesis of aspartame precursor using organic-solvent-stable PST-01 protease in monophasic aqueous-organic solvent systems.
abstract: The PST-01 protease is a metalloprotease that has zinc ion at the active center and is very stable in the presence of water-soluble organic solvents. The reaction rates and the equilibrium yields of the aspartame precursor N-carbobenzoxy-L-aspartyl-L-phenylalanine methyl ester (Cbz-Asp-Phe-OMe) synthesis from N-carbobenzoxy-L-aspartic acid (Cbz-Asp) and L-phenylalanine methyl ester (Phe-OMe) in the presence of water-soluble organic solvents were investigated under various conditions. Higher reaction rate and yield of Cbz-Asp-Phe-OMe were attained by the PST-01 protease when 30 mM Cbz-Asp and 500 mM Phe-OMe were used. The maximum reaction rate was obtained pH 8.0 and 37 degrees C. In the presence of dimethylsulfoxide (DMSO), glycerol, methanol, and ethylene glycol, higher reaction rates were obtained. The equilibrium yield was the highest in the presence of DMSO. The equilibrium yield of Cbz-Asp-Phe-OMe using the PST-01 protease attained 83% in the presence of 50% (v/v) DMSO.
authors.affiliation: Department of Chemical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
authors.forename: Shotaro
authors.initials: S
authors.lastname: Tsuchiyama
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Doukyu
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yasuda
authors.forename: Kosaku
authors.initials: K
authors.lastname: Ishimi
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Ogino
mesh_terms: D001218:Aspartame / Q000737:chemistry*; D001709:Biotechnology / Q000379:methods*; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D010452:Peptide Biosynthesis; D010447:Peptide Hydrolases / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000737:chemistry; D012997:Solvents / Q000737:chemistry
chemical_list: D010455:Peptides; D012997:Solvents; C461640:benzyloxycarsbonylphenylalanine cyanomethyl ester; C034515:phenylalanine methyl ester; D010649:Phenylalanine; D010447:Peptide Hydrolases; D004121:Dimethyl Sulfoxide; D001218:Aspartame