Enzymatic reduction of mercurous and mercuric ions in Bacillus cereus

A strain of Bacillus cereus, which can grow in nutrient broth containing 50 microM HgCl2, was isolated from soil. Mercurous or mercuric ion dependent oxidation of reduced NADPH was demonstrated in crude extracts of cells grown in nutrient broth containing 10 microM HgCl2. The properties of this mercuric reductase were similar to those of the enzymes from R factor bearing Escherichia coli in substrate specificity, heat stability, requirement of sulfhydryl compounds, sensitivity to some heavy metal ions, and molecular weight.