from indigenous fermented foods and human gut ... - Thapar University

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Chapter II Review of Literature
IIc bacteriocins are grouped on the fact that their N- and C-termini are covalently linked,
resulting in a cyclic structure (Maqueda et al., 2004). Class II bacteriocins are small, heat-
stable, cationic and hydrophobic peptides. They are generally very stable at acidic pH and as
pH increases, their heat stability decreases. Moreover, bacteriocins are usually sensitive to
proteolytic enzymes, such as trypsin, proteinase K and protease (Chen and Hoover, 2003).
Unlike lantibiotics, class II bacteriocins are not subject to extensive post-translational
modification, but synthesized as precursor molecules mostly containing a leader peptide of
the so called double glycine type (Cotter et al., 2005; Håvarstein, Diep and Nes, 1995).