7‐ O ‐(2‐Amino‐2‐deoxy‐α‐ d ‐glucopyranosyl) l ‐ glycero ‐ d ‐ manno ‐heptose

Hydrolysis of the Bordetella pertussis endotoxin, extracted from both ‘phase I’ and ‘phase IV’ bacteria, with 4 M HCL for 1 h at 100°C, released the disaccharide named in the title; it was isolated by paper electrophoresis or by ion‐exchange chromatography in about 1 % yield (w/w). The structure of the heptose could be rigorously established by chemical degradation; the facts that the glucosaminidic linkage was hydrolysed by an enzyme preparation containing both, α and β‐N‐acetylglucosaminidase activities, whereas it was resistant to cleavage by pure β‐ N ‐acetyl‐glucosaminidase strongly support the assumption that the disaccharide contains an α‐ d ‐glucosaminide linkage.