几种金属离子对文昌鱼酸性磷酸酶的影响

Effect of some Metal Ions on the Acid Phosphatasefrom Branchiostoma belcheri

几种金属离子对酶活力的影响，Ｆｅ￣（２＋）对酶活力没有抑制，Ｆｅ￣（３＋）有激活作用，Ｍｎ￣（２＋）、Ｃｏ￣（２＋）、Ｍｉ￣（２＋）抑制甚微，Ｃｄ￣（２＋）稍有抑制，而Ｚｎ￣（２＋）、Ａｇ￣（２＋）、Ｃｕ￣（２＋）、Ｈｇ￣（２＋）对酶活力有明显的抑制作用，其抑制强度依次为Ｈｇ￣（２＋）＞Ｃｕ￣（２＋）＞Ａｇ￣＋＞Ｚｎ￣（２＋）。随着Ｈｇ￣（２＋）、Ｃｕ￣（２＋）浓度增大而抑制作用加强，其抑制表现为竞争性类型，抑制常数Ｋｉ分别为１．１２×１０￣（－４）ｍｏｌ／Ｌ和３．７０×１０￣（－４）ｍｏｌ／Ｌ。金属离子影响酶活力，同时也影响了酶的构象，文中分别对荧光发射光谱和紫外－可见吸收光谱的变化加以讨论。

A survey of effect of metal ions on the ACPase(EC, 3. 1. 3. 2)from Branchios-toma belcheri shows that Fe￣(3+) activate the enzyme;Mn￣(2+) ,Co￣(2+) ,Ni￣(2+) , Cd￣(2+) inhibit the enzyme with aslight; Hg￣(2+)>Cu￣(2+)>Ag￣(2+) >Zn￣(2+) inhibit the enzyme activity distinctly. Kinetic analysis of the inhi-bition by the metul ions shows that the inhibition of Hg￣(2+) and Cu￣(2+) ions on the enzyme is found to beof competitive ap and the inhibition constants are found to be 1 . 12 × 10￣(-4) mol/L and 3. 70× 10￣(-4)mol/L respectively. The changes of the UV-visible spectra and the fluorescence intensity of the en-zyme effect by metal ions show that the enzyme conformation change while the enzyme catalytic activ-ity reduce.