The Hofmann degradation of glutamine residues in gliadin

Abstract

After subjection of N-acetylglutamine to the Hofmann degradation with alkaline hypobromite, l( + )-[alpha][gamma]-diaminobutyric acid could be isolated in 50% yield by successive precipitation with phosphotungstic and flavianic acids. The base could also be isolated from wheat gliadin after similar treatment with alkaline hypobromite, followed by acid hydrolysis. The best yields, corrected for minimum losses in isolation, were equivalent to 14-16.5% of the glutamic acid residues in the protein. At least this portion of the glutamic acid must exist in the intact gliadin as the glutamine residue. Salts of the base with flavianic and oxalic acids were characterized.