PURIFICATION OF PLASMA-MEMBRANE PENICILLINASE FROM BACILLUS-LICHENIFORMIS 749/C AND COMPARISON WITH EXOENZYME

Abstract

The membrane penicillinase of B. licheniformis 749/C was demonstrated to be a phospholipoprotein. The homogeneous enzyme gives a positive reaction for P and for unsaturated fatty acids, has a MW of 33,000 in contrast to 29,000 for the exoenzyme and contains 8-9 additional residues of aspartate or asparagine, 4-5 of serine, 7 of glutamate or glutamine and 4-5 of glycine/mol. The COOH-terminal sequence of both membrane and exoenzymes is -Met-Asn-Gln-Lys-COOH; the extra peptide portion present in the membrane enzyme is not attached to the COOH-terminus of the exoenzyme. Procedures which readily detected the lysine residue at the NH2 terminus of the exoenzyme did not yield a positive test with the membrane form. The NH2 terminus of the membrane enzyme may be blocked by or linked to the phospholipid. A procedure for the preparation of membrane penicillinase on a large scale and an improved method for purification of the exoenzyme were developed.