Interaction of yeast glucose 6-phosphate dehydrogenase with diverse triazine dyes: a study by means of affinity...

The interaction of yeast glucose 6-phosphate dehydrogenase with 31 triazine dye-stuffs was studied by means of affinity partitioning in an aqueous two-phase system using dye-liganded polyethyleneglycol and dextran as polymers. From the partition coefficients, K, of the enzyme in the presence and absence of the dye-polymer the term delta log K was calculated which corresponds to the actual interaction of the enzyme with the dye molecule. Quantitative data concerning the maximum extraction power delta logmax as well as the affinity of the dyes to the enzyme (expressed as percentage of dye-liganded polymer in the system at 0.5 X delta log Kmax) were derived. The influence of several effectors of the enzyme on the partition revealed that NADP+ and NADPH act competitively for a large number of dyes investigated.