Purification and properties of porphobilinogen deaminase from wheat germ

Abstract

Porphobilinogen deaminase from wheat germ was purified about 1000-fold. A series of DEAE-cellulose fractionations gave varying yields of uroporphyrin formation. The properties of the purified wheat germ enzyme were studied and compared with PBG deaminases from other origins such as Swiss chard leaves, human erythrocytes, and Rhodospirillum rubrum. A series of inhibitory effects on the enzyme were examined and the results are discussed in terms of enzyme structure and reactivity. The substrate specificity of the enzyme toward several 2-methylamino pyrroles was examined. A dithionite-activated protein factor was also isolated from wheat germ and Swiss chard and was found to consume PBG in a special way and to interact with the PBG-deaminase by inhibiting its activity. An hypothesis of the mode of action of deaminase is discussed in light of the data presented.