T. Nakajima et E. Ichishima, CHEMICAL-STRUCTURE OF THE GALACTOMANNAN MOIETY IN THE CELL-WALL GLYCOPROTEINS OF ASPERGILLUS-ORYZAE, Journal of fermentation and bioengineering, 78(6), 1994, pp. 472-475
The galactomannan-protein (GMP) containing 89% of carbohydrate and 11%
of protein was purified from the hyphal walls of Aspergillus oryzae.
The polymer contains both N- and O-linked carbohydrate chains. Mild al
kali treatment of the polymer yielded mannose and alpha-1,2-mannobiose
. The alkali-resistant polymer was composed of 14% of protein and 86%
of carbohydrate containing mannose and galactose with the ratio of 5:3
. Mild acid treatment of the alkali-resistant polymer caused a great c
hange in optical rotation from -15 degrees to +63 degrees with complet
e removal of galactose residues, and the residual polymer was a mannop
rotein of which side chains were completely hydrolyzed by a bacterial
alpha-1,2-mannosidase. The structural analyses with H-1- and C-13-NMR
spectroscopies of native, alkali-degraded, alkali-acid degraded polyme
rs and their acetolysis products indicate that the polysaccharide part
of the polymer has an alpha-1,6-linked mannan backbone with side chai
n consisting of single mannose residues linked via an alpha-1,2 bond a
nd almost all of the side chain consisting of nonreducing terminal man
nose residues are substituted by beta-galactofuranose residues.