Which buffer solution to use for Ninhydrin in a pepsin-mediated (acids added) digestion experiment?
Ninhydrin (triketohydrindene hydrate) is a chemical used to detect ammonia or primary and secondary amines. When reacting with these free amines, a deep blue or purple color known as Ruhemann’s purple is evolved. Ninhydrin is most commonly used to detect fingerprints, as amines left over from peptides and proteins (terminal amines or lysine residues) sloughed off in fingerprints react with ninhydrin.Ninhydrin can also be used to monitor deprotection in solid phase peptide synthesis (Kaiser Test).[2] When the growing peptide chain is deprotected, a ninhydrin test yields blue. If the next peptide residue is coupled then the test is colorless or yellow. Ninhydrin is also used in amino acid analysis of proteins: Most of the amino acids are hydrolyzed and reacted with ninhydrin except proline; Also, certain amino acid chains are degraded. Therefore, separate analysis is required for identifying such amino acids that either react differently or don’t react at all with ninhydrin. The rest of
