The terminal amino acids of wheat gliadin

Abstract

Wheat gliadin has been found by two different methods to contain three N-terminal histidine residues for each molecular weight of 27,000. Trace amounts of N-terminal aspartic acid, glutamic acid, alanine, valine, and serine were also detected in the preparation used. Hydrolysis in boiling hydrochloric acid partially destroyed the di-2,4-dinitrophenyl derivative of histidine. Losses of from 5% to 25% occurred depending upon the time and conditions of hydrolysis. Carboxypeptidase did not release free amino acids from wheat gliadin but qualitative evidence for the occurrence of C-terminal glutamic acid and C-terminal "leucine" was obtained.