ARGINASE OF BACILLUS-BREVIS NAGANO - PURIFICATION, PROPERTIES, AND IMPLICATION IN GRAMICIDIN-S BIOSYNTHESIS

An arginase [EC 3.5.3.1] was purified to homogeneous state from a gram icidin S-producing Bacillus brevis Nagano. The enzyme has a molecular weight of about 180,000 on gel filtration. The subunit molecular weigh t is 32,000 by sodium dodecyl sulfate polyacrylamide gel electrophores is, indicating that the enzyme is hexameric, The optimum pH is found n ear 10.0. Mn2+ is essential for its activity and Fe2+, Co2+, Ni2+, and Mg2+ cannot replace Mn2+. The enzyme is highly specific for L-arginin e with a K-m value of 12.8 mM for L-arginine, which is similar to that of liver-type arginase in ureotelic animals. B. brevis arginase is ap parently induced by the addition of L-arginine to the glutamate medium . The increased formation of L-ornithine, a constituent amino acid of gramicidin S, by arginase may be involved in the accelerated productio n of gramicidin S by B. brevis in the presence of L-arginine in the gr owth medium. (C) 1997 Academic Press.