Purification and characterization of chemotactic methylesterase from Bacillus subtilis

Abstract
By utilization of methanol evolution as an assay, a protein methylesterase from B. subtilis was purified. A 1200-fold purification was achieved by CM-Bio-Gel A, hydroxylapatite and Bio-Gel P-60 column chromatography. Gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicate the enzyme is a monomer of 41,000 in MW. The enzyme is stabilized and activated by aqueous glycerol solutions. Methyl-accepting chemotaxis proteins (MCP) serve as substrates for the enzyme. The enzyme requires divalent cation for activity, with maximum activity obtained at 1.1 mM Mg2+. The enzyme is most active at pH 7.5 and at 28.degree. C. Methylesterase has an apprent Km for methylated MCP of .apprx. 10 nM.