Salt Form
Salt Form — The ionic form of a peptide complexed with a counterion such as trifluoroacetate (TFA) or acetate, affecting solubility, stability, and net peptide content.
What Is a Salt Form?
A salt form is the ionic complex of a peptide with a counterion. Most synthetic peptides are supplied as trifluoroacetate (TFA) salts from RP-HPLC purification. The salt form affects peptide weight, solubility, stability, and biological compatibility. Net peptide content varies significantly by salt form.
Common Salt Forms
- TFA salt: Default from RP-HPLC. NPC 60-75%. TFA may interfere with some cell assays
- Acetate salt: TFA exchanged for acetate. NPC 75-85%. More biocompatible
- HCl salt: NPC 80-90%. Preferred for in vivo and clinical formulations
- Conversion: Counterion exchange by lyophilization from dilute acetic acid or HCl
Frequently Asked Questions
What is Salt Form?
The ionic form of a peptide complexed with a counterion such as trifluoroacetate (TFA) or acetate, affecting solubility, stability, and net peptide content.
Why is Salt Form important in peptide research?
Salt Form is a fundamental concept in chemistry as it relates to peptide science. It directly influences experimental design, compound characterization, and the reliability of research outcomes across biochemistry and molecular biology disciplines.