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以质粒ｐ Ｓ Ｐ Ｏ Ｒ Ｔ１ 为底物研究了高压力对 Ｉ Ｉ型限制性内切酶 Ｈｉｎｄ Ｉ Ｉ Ｉ和 Ｘｂａ Ｉ反应的影响。高压力未引起两酶底物碱基特异性的改变， 但二者反应活力均随压力升高而逐渐下降， Ｘｂａ Ｉ对高压力更敏感。引起 Ｈｉｎｄ Ｉ Ｉ Ｉ和 Ｘｂａ Ｉ限制性内切酶活性完全丧失的压力分别为２００ 和１８０ Ｍ Ｐａ， 半失活压力分别为１３０ 和７５ Ｍ Ｐａ。酶单独经高压力作用后， Ｈｉｎｄ Ｉ Ｉ Ｉ可迅速恢复原活性， 而 Ｘｂａ Ｉ则不可逆失活，二者结构稳定性有较大差异。根据在不同压力下的酶反应抑制率估算 Ｈｉｎｄ Ｉ Ｉ Ｉ和 Ｘｂａ Ｉ反应的标准摩尔体积变化分别为２１３ 和１０３ ｍｌ／ｍｏｌ。
The effect of high pressure on the reaction of I type I restriction enzymes Hind I I and Xba I was investigated using plasmid pS P O R T1 as a substrate. High pressure did not cause base-specific changes in the two enzyme substrates, but both reactive vitality decreased gradually with increasing pressure, Xba I is more sensitive to high pressure. The pressures causing complete loss of Hind I I and Xba I restriction endonuclease activity were 200 and 180 M Pa, respectively, and the semi-inactivation pressures were 130 and 75 M Pa, respectively. Hind I I I can quickly restore its original activity, but Xba I is irreversibly inactivated. The stability of the two structures is quite different. The standard molar volume changes for the reaction of Hind I I and Xba I were estimated as 213 and 103 ml / mol, respectively, based on the inhibition of enzyme reaction at different pressures.