Can the BCA Protein Assay Kit quantitate peptides?
Peptides smaller than 2,000 Da cannot be quantitated with the BCA assay because color formation is dependent on protein’s macromolecular structure, the number of peptide bonds, and the presence of cysteine, cystine, tryptophan and tyrosine. For peptides smaller than 2,000 Da, try using Fluoraldehyde o-Phthalaldehyde Reagent Solution (Product # 26025). This reagent will detect amino groups on small peptides by fluorescence.
