[Purification and some characteristics of germins G and psiG from wheat]

By affinity chromatography, germins G and psiG were purified from roots of wheat seedling and wheat embryos imbibition for 4 h. Characterization of the germins G and psiG were studied. The results showed that G and psiG were stable at temperatures lower than 60 degrees C, and had an optimum pH at 3.5. The Km value of G for oxalate was 0.084 mmol/L, while that of psiG was 0.053 mmol/L. Oxalate showed substrate inhibition effect above 0.2 mmol/L on G and psiG. EDTA, NH(+)(4), Mn(2+), Mg(2+), Na(+) and K(+) at a concentration of 0.1 mmol/L had no effect on OxO activity. CO(2-)(3), NO(-)(3) and SO(2-)(4) at a concentration of 0.1 mmol/L inhibited partially the activities of G and psiG, 0.1 mmol/L Cu(2+), Fe(2+), Al(3+) completely inhibited the activities of G and psiG, but addition of 0.1 mmol/L EDTA partially relieved the inhibition, which indicated that metal cations may make the oxalate unavailable by chelating it. H(2)PO(-)(4) and HPO(2-)(4) inhibited the activity of G, but had no effect on psiG. Riboflavin, FMN and FAD inhibited psiG, but FMN and FAD had no effect on G.