Enzyme immunoassay system for estimating the ultrastructure of (1,6)-branched (1,3)-β-glucans

A sandwich-type enzyme immunoassay (EIA) system for quantifying branched (1,3)-beta-glucans was established. A polyclonal antibody was purified with antigen-conjugated aminocellulofine and labelled with biotin to be used as the detection antibody. The reactivity of the antibody was restricted to only (1,6)-branched (1,3)-beta-glucans. Molecular weight dependency of (1,6)-branched (1,3)-beta-glucan in the reactivity was also observed. Alkaline-treated (1,6)-branched (1,3)-beta-glucan which was reported to be a single helical conformer, showed a lower absorbance compared to the untreated triple helix conformer. The conformational alteration of the single helix to the triple helix was produced by heating for 15 min at 100 degrees C. The results suggest that EIA has higher reactivity to the triple helical ultrastructure of (1,6)-branched (1,3)-beta-glucans, and can be applied to estimate the conformational changes of (1,6)-branched (1,3)-beta-glucans. (C) 1999 Elsevier Science Ltd. All rights reserved.