Peptide counter ions

The industry standard is to provide peptides as a Trifluoroacetic acid salt, TFA. Thus the lyophilized powder consists of peptide material, counter ions and bound water. Unless explicitly stated otherwise, amounts are in terms of weight of the powder – i.e. gross weight, as opposed to net weight - and having TFA as the counter ion.

For most applications the presence of TFA is not an issue. In others, particularly when working with cells, it may be a problem. In these cases, taking cell penetrating peptides (e.g. Penetratin) as an example, one may want to consider the use of acetate as counter ion instead. Acetate is an excellent choice in most cases, but the additional work and material loss in the conversion does have an impact on cost.

Additional information

• Net peptide content, amino acid analysis and elemental analysis
• Peptide stability, storage and solubilisation

Since the beginning in 1992, Innovagen has been providing the scientific community with molecular biology services and research materials. The experience we have gained over 20 years or so is the basis of our commitment to the production of high quality peptides and our ambition of giving our clients excellent customer service.