Comparative Studies on Extracellular Penicillinases of the Same Structural Gene, penP, Expressed in Bacillus licheniformis and Bacillus subtilis

SUMMARY: Extracellular penicillinases produced by Bacillus licheniformis ATCC 9945A and Bacillus subtilis from the same structural gene, penP, were compared. The two strains secreted the same exolarge penicillinase (mol. wt, 30500; isoelectric point, pI = 5.00-5.04; NH2-terminal amino acid, Ser). In contrast, the exo-small enzyme from Bacillus subtilis (mol. wt, 29500; pI = 5.00-5.04; NH2-terminal amino acid, Glu or Asn) was slightly different from that of Bacillus licheniformis (mol. wt, 29500; pI = 5.13; NH2-terminal amino acid, Lys). The difference in the NH2-terminal residue is most probably due to differences in degradation by host-specific proteolytic enzymes.