Purification and properties of a second enzyme catalyzing the splitting of carbon-mercury linkages from mercury-resistant Pseudomonas K-62

Abstract

An enzyme (splitting enzyme 2) which catalyzes the splitting of C-Hg linkage of arylmercury compounds was found in extracts of Hg-resistnat Pseudomonas K-62. This enzyme was purified about 725-fold by treatment with streptomycin, precipitation with (NH4)2SO4, and successive chromatography on Sephadex G-75 and DEAE-cellulose. A purified preparation of the enzyme showed a single band in electrophoresis either on polyacrylamide or sodium dodecyl sulfate-containing polyacrylamide gels. The MW of the enzyme was 20,000 (determined by Sephadex G-75 gel filtration) and 17,000 (determined by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis). The enzyme showed a Km of 180 .mu.M and a Vmax of 3.1 .mu.mol/min per mg for p-chloromercuribenzoic acid and a Km of 250 .mu.M and a Vmax of 20 .mu.mol/min per mg for phenylmercuric acetate. The optimum temperature and pH for the reaction were 40.degree. C and 5.0, respectively.