Nisin, also known as Lacticin or transliterated as Nisin, is a polypeptide substance produced by Lactococcus lactis.

Basic Characteristics of Nisin:

Chemical Composition: Nisin consists of 34 amino acid residues, with a molecular weight of approximately 3,500 Da (specifically 3,354.07 g/mol). Its molecular structure includes five uncommon amino acids: ABA, DHA, DHB, ALA-S-ALA, and ALA-S-ABA, which form five internal rings through thioether bonds. Its active molecules are often dimers or tetramers.

Appearance: Nisin appears as a white to light yellow or light brown powder.

Solubility: The solubility of Nisin in water is pH-dependent. At a pH of 2.5, the solubility is 12%; at a pH of 5.0, the solubility decreases to 4%; it is almost insoluble in neutral and alkaline conditions.

Stability: Nisin exhibits good heat resistance at a pH of 2, but its heat resistance decreases when the pH exceeds 5. Additionally, it is resistant to acidic conditions.