Purification and nature of the antibiotic nisin

Abstract

A single prepn. of nisin was resolved into at least 4 active polypeptides, nisin A, B, C and D, by counter-current distr. between solvents. Nisins A and B show similar activity against Streptococcus agalactiae, and nisins C and D are about 20% as active as A and B. Nisins A, B and C appear to contain leucine and/or isoleucine, valine, alanine, glycine, proline, aspartic acid, histidine, lysine, methionine, lanthionine and a cystathionine or allocystathionine. Cystathionine appears to be present in larger amt. by wt. than most of the other amino acids. Nisin D contains glutamic acid but no valine or methionine. Various commercial prepns. of nisin were found to be similar in amino acid composition, but some batches contain glutamic acid and serine, which are absent from nisins A, B and C. The nisin polypeptides show some resemblance in their properties to the antibiotic subtilin.