Amino-acid sequence of the coeliac active gliadin peptide B 3142.

Peptide B 3142, which has been isolated from a peptic tryptic digest of whole gliadin by several separation steps [1], was examined for coeliac activity in an immunological test and in an organ-culture test, comparing enlarged groups of coeliac patients and control persons. In both test systems the peptide shows a coeliac specific effect. The N-terminal sequence analysis (EDMAN degradation), the C-terminal sequence analysis (incubation with carboxypeptidase Y) and the sequence determination of peptides, obtained from B 3142 by digestion with papain and chymotrypsin, result in the following total amino-acid sequence: H-Val-Pro-Val-Pro-Gln-Leu-Gln-Pro-Gln-Asn-Pro-Ser-Gln-Gln- Gln-Pro-Gln-Glu-Gln-Val-Pro-Leu-Val-Gln-Gln-Gln-Gln-Phe-Pro-Gly-Gln-Gln- Gln-Pro-Phe-Pro-Pro-Gln-Gln-Pro-Tyr-Pro-Gln-Pro-Gln-Pro-Phe-Pro-Ser-Gln- Gln-Pro-Tyr-OH. The 53 amino-acid residues correspond to a molecular mass of 6,129 g/mol.