Studies on Respiratory Enzymes in Rice Kernel

Part IV Purification and Some Properties of a Flavoprotein from Rice Embryo

Abstract

A flavoprotein was purified from rice embryo by means of ammonium sulfate fractionation, ion-exchange chromatography on CM-Sephadex C-50 and DEAE-Sephadex A-50, and gel filtration chromatography on Sephadex G-75 and G-100. A molecular weight of 37000 was determined by gel filtration on Sephadex G-100. The flavoprotein was shown to be homogeneous, with a sedimentation coefficient of 2.5S, in the sedimentation analysis, and exhibited an absorption spectrum characteristic of flavoprotein with absorption maxima at 276, 394 and 443mμ and shoulders at about 435, 465 and 485mμ. The prosthetic group of the protein was identified as flavin adenine dinucleotide. The flavoprotein was found to resemble the spinach chloroplast NADPH diaphorase in a number of aspects so far examined.