Aminopeptidases of Bacillus subtilis

The production of aminopeptidases, intracellularly or extracellularly, by many bacterial species has been noted (4, 5, 28). In the genus Bacillus, Aubert and Millet (2) reported an aminopeptidase in cells of _B. megaterium which increased five-fold in activity during sporulation. Hall, Kunkel and Prescott reported an extracellular aminopeptidase in culture filtrated of B. licheniformis which has a pH optimum of 8.5 - 9, and was activated by Co ions (15). Two aminopeptidases haye also been reported in B^. stearothermophi 1 us (25, 29).

In B. subtilis, Matsumura, et al_., (23) and ainamiura, et al., (24) found two aminopeptidases in cells of this species which could be separated from each other on columns of diethylaminoethyl (DEAE) cellulose. Minamiura, ejt aj, reported that one of these two enzymes hydrolyzed D-leucyl-glycyl-glycine. Wagner, Chung, and Ray (32) described an extracellular aminopeptidase in cultures of B. subtilis which they contend is secreted, under appropriate conditions, by intact cells into the medium. The pH optimum of this enzyme was 8.0, and Co was found to activate it.