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Chapter IV: Results
Fig. 4.8 Tricine SDS-PAGE of the bactriocin: Lane 1, molecular weight markers; lane 2,
Bacteriocin, (B), Zone of growth inhibition, corresponding to the position of the peptide
band in lane A2. The gel was overlaid with L. monocytogens (approx. 10 5 CFU/ml),
embedded in BHI soft agar
4.10.3 N-terminal amino acid sequence of bacteriocin
The N-terminal amino acid sequence of purified bacteriocin, indicated that the N
terminus strarts with alanine and end with glycine. The amino acid analysis of this band
revealed the following partial sequence: “ARSYGNGVYCGNKKCWGRGEATEG”. Amino
acids 1 to 12 and 14 to 24 revealed that the 21st amino acid was alanine (A) and the 24th
amino acid was glycine (G). The molecular mass was 2563.94 Da and the isoelectric point
was at pH 8.77. The bacteriocin possess the net charge 2 and had 4 hydrophobic residues.
Table 4.24: The physiochemical properties of the peptide sequence
AA N° % AA N° % AA N° %
Ala 2 8.33 Ile 0 0.00 Arg 2 8.33
Cys 2 8.33 Lys 2 8.33 Ser 1 4.17
Asp 0 0.00 Leu 0 0.00 Thr 1 4.17
Glu 2 8.33 Met 0 0.00 Val 1 4.17
Phe 0 0.00 Asn 2 8.33 Trp 1 4.17
Gly 6 25.00 Pro 0 0.00 Tyr 2 8.33
His 0 0.00 Gln 0 0.00
Total 24