D-Gluconate Transport in Bacillus subtilis

and non-uniformity of the oligosaccharides themselves, would indicate that the toxicity is a property of a number of molecules. For this reason large-scale chromatographic techniques were avoided since they would result in a distribution of toxicity across the chromatographic profile. Instead the role of carbohydrate was investigated by the selective removal of the sugar residues glycosidic linkages by using a glycosidase preparation from Aspergillus niger, which was essentially free of proteolytic activity. Gliadin was incubated with this enzyme preparation at pH4.5, and then was dialysed. An examination of the diffusate byg.1.c. showed that all four glycosides were quantitatively recovered with meso-inositol as an internal standard. Acid-catalysed methanolysis of the retentate followed by g.1.c. confirmed this finding. Quantitation of the release of peptide material with ninhydrin and high-voltage electrophoresis showed a negligible release of ninhydrinpositive material. A comparison of peptide maps of treated and untreated gliadin showed that the enzyme treatment did not alter the primary structure of the protein, and that there was no deamidation of glutamine residues. The presentation of carbohydrasetreated gliadin to coeliac patients in remission demonstrated that this procedure abolishes gliadin toxicity (Phelan et al., 1974).