Crude peptides are not recommended for biological assays. Crude peptides may contain large amounts of non-peptide impurities such as residual solvents, scavengers from cleavage, TFA and other truncated peptides. TFA cannot be totally removed. Peptides are usually delivered as TFA salt. If residual TFA is a problem for your experiment, we recommend other salt forms such as acetate and hydrochloride. These salt forms are usually 20-30% more expensive than the regular TFA salt. This is due to the peptide loss that takes place during the salt conversion and the greater amounts of raw materials required.
 
>70% purity
· Peptide arrays
· Antigens for antibody production
· Competitive elution chromatography
· ELISA standards for measuring antisera titers
 
>80% purity
· Western blotting studies (non-quantitative)
· Enzyme-substrate studies (non-quantitative)
· Peptide blocking studies (non-quantitative)
· Affinity purification
· Phosphorylation assays
· Protein electrophoresis applications and immunocytochemistry
 
>95% purity
· ELISA standards and RIA protocols (quantitative)
· Receptor-ligand interaction studies (quantitative)
· In vitro bioassays and in vivo studies
· Enzyme studies and blocking assays (quantitative)
· NMR studies
· Mass spectrometry
· Other quantitative assays
 
>98% purity
· SAR Studies
· Clinical trials
· APIs (Active Pharmaceutical Ingredients)
· Commercial products
· X-ray crystallography studies
· Other sensitive experiments: enzyme-substrate studies, receptor-ligand interaction studies, blocking and competition assays