AQUEOUS 2-PHASE EXTRACTION OF DEHYDROGENASES USING TRIAZINE DYES IN PEG PHOSPHATE SYSTEMS

Group-specific affinity extraction of dehydrogenases, such as baker's yeast alcohol dehydrogenase, rabbit muscle lactic dehydrogenase, bovine liver glutamic dehydrogenase and yeast glucose-6-phosphate dehydrogenase, was studied using triazine dyes in polyethylene glycol (PEG)/potassium phosphate aqueous two-phase systems. The parameters and factors determining affinity partition have been evaluated. Triazine dye ligands were found to have approximately the same inhibition constants for alcohol and glutamic dehydrogenases in the presence of the top phase of PEG/phosphate system as those in the simple buffer solution without the two-phase system. Thus, affinity partitioning is observed for these enzymes in a PEG/phosphate system, except for a few enzymes which have phosphate as an inhibitor or activator. PEG/phosphate systems have advantages of high ligand partition coefficients, high enzyme selectivities and low costs as compared to PEG/dextran systems. The selection and optimization of the affinity extraction processes have also been discussed.