Manganese Ion-dependent Production of Phosphodiesterase by Alkalophilic Bacillus No. A-40-2 and Its Properties

Abstract

Phosphodiesterase production with bis-p-nitrophenyl phosphate as a substrate by alkalophilic Bacillus No. A-40-2 increased with increasing Mn²⁺ concentration, showing maximum productivity at 10 mM. The enzyme production was negligible in the medium without Mn²⁺. The simultaneous addition of 10 mM Mn²⁺ and one of the several cations Mg²⁺, Co²⁺, Mo⁶⁺, and Pb²⁺ at suitable concentrations stimulated the enzyme production 1.8-fold at most over that with only 10 mM Mn²⁺ . Inorganic phosphate hardly repressed the enzyme production. The enzyme was purified homogeneously. The purified enzyme had the optimum pH of 7.5 and was fairly stable from pH 7-11. The enzyme hydrolyzed 2', 3'-cyclic-nucleotides and 3'-nucleotides, but did not hydrolyze 3', 5'-cyclic-nucleotides or 5'-nucleotides, indicating it to be a 2', 3'-cyclic-micleotide 2'-phosphodiesterase (EC 3.1.4.16). The enzyme had activity without metals, but Mg²⁺, Ca²⁺, Ba²⁺, and Mo⁶⁺ activated the enzyme reaction.