BETA-GLUCOSYL AND ALPHA-GALACTOSYL YARIV REAGENTS BIND TO CELLULOSE AND OTHER GLUCANS

Yariv reagent ucopyranosyloxyphenylazo)-2,4,6-trihydroxybenzene] has b een used in the purification/quantification of arabinogalactan-protein s and as a histochemical reagent to localize arabinogalactan-proteins in plant tissues. When developing cotton fiber cells were stained with beta-glucosyl Yariv reagent, interference from other cell wall polyme rs, especially cellulose, was suspected. In order to examine this pote ntial interference, we have developed two dye-binding assays to measur e the binding of Yariv reagent in the presence of various carbohydrate polymers. Reaction conditions such as pH, ionic strength, and exposur e time in the standard binding assays were investigated. The results s how that beta-glucosyl and alpha-galactosyl Yariv reagents bind to cel lulose and several other glucans. Treatments with excess glucose in th e assay to inhibit binding were only partially effective in preventing beta-glucosyl Yariv reagent from binding to cellulose.