Abstract A destabilizing effect at pH 7 of sodium phosphate on several lipases immobilized via interfacial activation is shown in this work. This paper investigates if this destabilizing effect is extended to other inactivation conditions, immobilization protocols or even other immobilized enzymes (ficin, trypsin, β-galactosidase, β-glucosidase, laccase, glucose oxidase and catalase). As lipases, those from Candida antarctica (A and B), Candida rugosa and Rhizomucor miehei have been used. Results confirm the very negative effect of 100 mM sodium phosphate at pH 7.0 for the stability of all studied lipases immobilized on octyl agarose, while using glutaraldehyde-support the effect is smaller (still very significant using CALA) and in some cases the effect disappeared (e.g., using CALB). The change of the pH to 5.0 or 9.0, or the addition of 1 M NaCl reduced the negative effect of the phosphate in some instances (e.g., at pH 5.0, this negative effect is only relevant for CALB). Regarding the other enzymes, only the monomeric β-galactosidase from Aspergillus oryzae is strongly destabilized by the phosphate buffer. This way, the immobilization protocol and the inactivation conditions strongly modulate the negative effect of sodium phosphate on the stability of immobilized lipases, and this effect is not extended to other enzymes.

中文翻译：

---

磷酸根阴离子对固定化酶稳定性的影响。酶性质、固定方案和灭活条件的影响

摘要 这项工作显示了磷酸钠在 pH 7 时对通过界面活化固定的几种脂肪酶的不稳定作用。本文研究了这种不稳定效应是否扩展到其他灭活条件、固定化方案甚至其他固定化酶（无花果蛋白酶、胰蛋白酶、β-半乳糖苷酶、β-葡萄糖苷酶、漆酶、葡萄糖氧化酶和过氧化氢酶）。作为脂肪酶，已经使用了来自南极假丝酵母（A 和 B）、红假丝酵母和米黑根霉的脂肪酶。结果证实，pH 7.0 的 100 mM 磷酸钠对固定在辛基琼脂糖上的所有研究脂肪酶的稳定性有非常负面的影响，而使用戊二醛支持的影响较小（使用 CALA 仍然非常显着），并且在某些情况下，这种影响消失了（例如，使用 CALB）。pH 值变为 5.0 或 9.0，或在某些情况下，添加 1 M NaCl 降低了磷酸盐的负面影响（例如，在 pH 5.0 时，这种负面影响仅与 CALB 相关）。关于其他酶，只有来自米曲霉的单体 β-半乳糖苷酶被磷酸盐缓冲液强烈破坏。这样，固定化方案和灭活条件强烈调节磷酸钠对固定化脂肪酶稳定性的负面影响，并且这种影响不会扩展到其他酶。