Tezuka T, Tonomura K
J Biochem. 1976 Jul;80(1):79-87. doi: 10.1093/oxfordjournals.jbchem.a131261.
An enzyme (S-1) which catalyzes the splitting of carbon-mercury linkages of organomercury compounds was purified about 24-fold from the cell-free extract of mercury-resistant Pseudomonas K-62 strain by treatment with streptomycin, precipitation with ammonium sulfate, and successive chromatography on Sephadex G-150, DEAE-Sephadex, and DEAE-cellulose. A purified preparation of the enzyme showed a single band on polyacrylamide gel electrophoresis, and was colorless. The molecular weight of the enzyme was estimated to be 19,000, and Km was 5.3 X 10(-5) M for p-chloromercuribenzoic acid (PCMB). The temperature and pH optimum for the reaction were 50degrees and 7.0, respectively. The enzyme was capable of catalyzing the decomposition of methylmercuric chloride (MMC), ethylmercuric chloride (EMC), phenylmercuric acetate (PMA), and PCMB in the presence of a sulfhydryl compound to form a mercuric ion plus methane, ethane, benzene, or benzoic acid, respectively. The mercuric ion thus formed was reduced to metallic mercury by metallic mercury-releasing enzyme (MMR-enzyme).
通过用链霉素处理、硫酸铵沉淀以及在Sephadex G - 150、DEAE - Sephadex和DEAE - 纤维素上连续层析，从耐汞假单胞菌K - 62菌株的无细胞提取物中纯化出一种催化有机汞化合物碳 - 汞键断裂的酶（S - 1），纯化倍数约为24倍。该酶的纯化制剂在聚丙烯酰胺凝胶电泳上显示为单一带，且无色。该酶的分子量估计为19,000，对对氯汞苯甲酸（PCMB）的Km为5.3×10⁻⁵ M。反应的最适温度和pH分别为50℃和7.0。在巯基化合物存在下，该酶能够催化甲基氯化汞（MMC）、乙基氯化汞（EMC）、苯基醋酸汞（PMA）和PCMB的分解，分别形成汞离子加甲烷、乙烷、苯或苯甲酸。由此形成的汞离子被金属汞释放酶（MMR - 酶）还原为金属汞。
