PURIFICATION AND PARTIAL AMINO-ACID-SEQUENCE OF BREVICIN-27, A BACTERIOCIN PRODUCED BY LACTOBACILLUS-BREVIS SB27

Brevicin 27, a bacteriocin produced by Lactobacillus brevis SB27, is i nhibitory mainly against closely related Lactobacillus brevis and Lact obacillus buchneri strains. It was purified from the culture supernata nt by a four-step purification procedure including ammonium sulfate pr ecipitation, cation exchange, hydrophobic interaction, and reverse-pha se, high performance liquid chromatographies. The purified bacteriocin was subjected to mass spectrometry, amino acid composition analysis, and sequencing by Edman degradation. It was shown to be an about 5200- Da basic protein containing a high proportion of lysine and of hydroph obic amino acids. The partial N-terminal amino acid sequence (25 resid ues) was unique when compared with the Protein Data Bank (PDB), Swiss Prot, and Protein Information Resource (PIR) data banks and to the tra nslated Gen Bank.