Zum Einfluss von anorganischem Phosphat auf die Phosphohydrolasen von Weizenembryonen (Triticum aestivum L.)

Phosphate is an effective inhibitor of the phosphohydrolases of wheat embryos (Triticum aestivum L.).In vitro the inhibition was competitive with K₁ = 4.48 × 10^-3 M (1.6 × 10^-3 M P₁, applied as KH₂PO₄).In vivo the inhibition with KH₂PO₄ was relatively low during germination (48 h), but inhibition increased when other P₁-compounds were used. In ungerminated embryos the phosphatase activity comprised three isozymes; the pattern of iaozymes changes during germination, but there was no influence of P₁ in comparison with the control. Concluding we may state that the activity of phosphohydrolases is regulated by an inhibition mechanism caused by P_i-concentration.