Antimicrobial peptide, Lactococcin G alpha2

• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

Lactococcin G is a lactococcal bacteriocin whose antimicrobial activity depends on the complementary action of two distinct peptides, designated alpha (α) and beta (β). The α peptide exists in two isoforms, α1 and α2, which are likely the same gene product but differ in configuration, with α1 demonstrating higher activity when combined with the β peptide. The α1 peptide contains 39 amino acid residues with a molecular weight of 4,376, while the β peptide contains 35 residues with a molecular weight of 4,109. Both peptides possess high isoelectric points, above 10, and are unmodified. The N-terminal halves of both α and β peptides can form amphiphilic α-helices, suggesting that lactococcin G functions as a pore-forming toxin that creates cell membrane channels through a barrel-stave mechanism. The C-terminal halves of both peptides consist largely of polar amino acids. When neither peptide is in excess, approximately 0.3 nM α1 and 0.04 nM β are required to induce 50% growth inhibition, indicating a potential interaction ratio of 7:1 or 8:1 (α:β).

• Nissen-Meyer J, Holo H, Håvarstein LS, Sletten K, Nes IF. A novel lactococcal bacteriocin whose activity depends on the complementary action of two peptides. J Bacteriol. 1992 Sep;174(17):5686-92. doi: 10.1128/jb.174.17.5686-5692.1992. PMID: 1512201; PMCID: PMC206516.

Trifluoroacetic acid (TFA) is a common counterion from the purification process using High-Performance Liquid Chromatography (HPLC). The presence of TFA can affect the peptide's net weight, appearance, and solubility.

Impact on Net Weight: The TFA salt contributes to the total mass of the product. In most cases, the peptide content constitutes >80% of the total weight, with TFA accounting for the remainder.

Solubility: TFA salts generally enhance the solubility of peptides in aqueous solutions.

In Biological Assays: For most standard in vitro assays, the residual TFA levels do not cause interference. However, for highly sensitive cellular or biochemical studies, please be aware of its presence.