Structure of a galactosaminoglycan from Cordyceps ophioglossoides

A water- and alkali-insoluble galactosaminoglycan (CON), precipitated with ammonium hydroxide from the culture filtrate of Cordyceps ophioglossoides, is composed mainly of 2-amino-2-deoxy-d-galactose (80.5%) together with small proportions of glucose, galactose, and mannose, protein (3.6%), and acetyl groups (1%). CON was eluted as a single peak in gel filtration, and the average molecular weight was estimated to be ～50,000. Partial, acid hydrolysis of CON gave small CON and homologous 2-amino-2-deoxy-d-galacto-oligosaccharides. Small CON (mol. wt. ～10,000) was soluble in water and composed only of 2-amino-2-deoxy-d-galactose. The results of methylation analysis, ¹³C-n.m.r. studies, and enzymic hydrolysis indicated small CON to be a (1→4)-linked 2-amino-2-deoxy-α-d-galactopyranan, and the ¹³C-n.m.r. data indicated the glycosidic linkage in the polygalactosamine moiety of CON to be the same as that of small CON.