title: Purification and characterization of cystathionine gamma-synthase type II from Bacillus sphaericus.
abstract: Cystathionine gamma-synthase type II, which catalyzes L-cystathionine synthesis from O-acetyl-L-homoserine and L-cysteine was purified from Bacillus sphaericus (IFO 3536) in seven steps. The purified enzyme appeared to be homogeneous by the results of polyacrylamide electrophoresis and ampholyte electrofocusing. The enzyme is a typical pyridoxal-P dependent enzyme, has a molecular mass of 165 kDa and consists of four subunits identical in molecular mass. The enzyme catalyzed the gamma-replacement reaction and the elimination reaction was hardly detected even when a large amount of enzyme was added. In the replacement reaction, O-acetyl-L-homoserine and the following thiol compounds: L and D-cysteine, L and D-homocysteine, sodium sulfide, various alkyl and aryl mercaptans, acted as the most suitable substrate to produce L-cystathionine and the corresponding S-substituted L-homocysteine derivatives.
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D019757:Carbon-Oxygen Lyases; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006710:Homocysteine / Q000096:biosynthesis; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D008190:Lyases / Q000302:isolation & purification* / Q000378:metabolism; D008970:Molecular Weight; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D006710:Homocysteine; C022696:O-succinylhomoserine (thiol)-lyase; D008190:Lyases; D019757:Carbon-Oxygen Lyases