| Abstract: | The agarose-coupled triazine dye Procion Red HE-3B has been demonstrated to be applicable as an affinity gel for the purification of five diverse hydrogenases, namely the soluble, NAD-specific and the membrane-bound hydrogenase of Alcaligenes eutrophus, the membrane-bound hydrogenase of the N2-fixing Alcaligenes latus, the reversible H2-evolving and the unidirectional H2-oxidizing hydrogenase of Clostridium pasteurianum. In the case of the soluble hydrogenase of A. eutrophus, chromatography on Procion Red-agarose even permitted the separation of inactive from active enzyme, thus yielding a 2-3-fold increase in specific activity. For the homogeneous enzyme preparation obtained after two column steps (Procion Red-agarose, DEAE-Sephacel), a specific activity of 121 mumol of H2 oxidized/min per mg of protein was determined. Kinetic studies with free Procion Red provided evidence that the diverse hydrogenases are competitively inhibited by the dye, each with respect to the electron carrier (NAD, Methylene Blue, Methyl Viologen), indicating a specific interaction between Procion Red and the catalytic centres of the enzymes. For the highly purified preparations of the soluble and the membrane-bound hydrogenase of A. eutrophus, in 50 mM-potassium phosphate, pH 7.0, Ki values for Procion Red of 103 and 19 microM have been determined. |
