Affinity interaction of hydroxypyruvate reductase from Methylophilus spp. with Cibacron blue F3GA-derived poly(HEMA EGDMA) microspheres: partial purification and characterization

A methylotrophic hydroxypyruvate reductase was partially purified and chara cterized from Methylophilus spp. using the biomimetic dye, Cibacron Blue F3 FA attached to poly(HEMA-EGDMA) microspheres. The absorption capacities of the dye-affinity microspheres were determined by changing pH and the concen tration of the proteins in the adsorption medium. Hydroxypyruvate reductase was desorbed from the dye-affinity support specifically with 2 mM NADH sol ution. The enzyme was purified 10.4-fold with 47% yield. The molecular mass and subunit molecular mass of the enzyme was estimated to be 75 kDa and 37 kDa on the basis of its mobility in polyacrylamide and SDS-polyacrylamide gels, respectively. This suggested a homogeneous dimer structure. The optim al pH was between 5.0 and 7.0, and the maximum enzyme activity was obtained at 50 degrees C. The K-m values of hydroxpyruvate reductase were 0.222 mM for hydroxpyruvate and 0.067 mM for NADH. (C) 1999 Elsevier Science Ltd. Al l rights reserved.