氟化鈉對酸性磷酸酶活性的抑制作用

Inhibitory Effect of Sodium Floride on Activity of Acid Phosphatase in Rice Plants

水稻幼苗經氟化鈉處理後，植株的根部及地上部生長皆受妨礙。離體下，氟化鈉也會抑制酸性磷酸酶的活性，其屬非競爭性的抑制作用。以p-NPP為酵素受質時的Km值為0.33 mM，而氟化鈉的Ki值為0.23 mM。粗抽出液在電泳圖上酸性磷酸酶呈出四群同功酵素。第一群同功酵素較耐氟化鈉的作用；第三群對氟化鈉則較敏感；其餘屬中度敏感者。

Plants treated with sodium floride showed the retardation of plant growth in shoot and root systems. In vitro, sodium floride also inhibits the activity of acid phosphatase activity. It is a noncompetitive inhibitor of acid phosphatase extracted from rice seedlings. Its Km value for pnitrophenyl phosphate (p-NPP) was 0.33 mM and Ki value for NaF is 0.23 mM. Crude extract of acid phosphatase from rice seedlings has four major groups of isozymes (group I, II, III, and VI). Group I isozymes are more tolerant to NaF, gropus III are more sensitive (group III) and the rest are intermediate.