Parameters determining affinity partitioning of yeast enzymes using polymer-bound triazine dye ligands

Triazine dyes, bound to polyethylene glycol, have been used to influence the partition of some enzymes within a dextran-polyethylene glycol-water two-phase system. The enzymes, present in a protein extract from baker's yeast, included glucose 6-phosphate dehydrogenase, glyceraldehyde phosphate dehydrogenase, 3-phospho-glycerate kinase and alcohol dehydrogenase. The partition coefficients of the enzymes could be changed by a factor of 10-500 in favour of the polyethylene glycol-rich phase, while the partition of bulk protein was much less affected. The influence of the concentration of polymer-bound dye and phase-forming polymers, temperature, pH, kind and concentration of salt and the presence of nucleotides on this affinity partitioning effect was studied. The extraction was effective even at high concentrations of dye and protein (40 g/l). A partial purification (32-fold) of glucose 6-phosphate dehydrogenase was carried out by an extraction in five steps.