乳酸脱氢酶在CTAB-戊醇反胶束体系中的催化动力学研究

以十六烷基三甲基溴化铵（CATB）-异辛烷-戊醇反胶束体系对乳酸脱氢酶（LDH）了固定化,探讨了体系含水量W0（W0=n（水）/n（CTAB）、CTAB浓度、戊醇体积比对LDH固定化的影响及游离酶和固定酶的催化动力学性质.结果表明：LDH进入反胶束的最佳条件是：体系含水量为4.3,CTAB浓度为0.24 mol/L,戊醇体积比为25%.对游离酶和固定化酶的酶促反应的最适pH值均为8.8,最适反应温度分别为52℃和30℃,米氏常数Km分别为65mmol/L和48mmol/L.在25℃时,游离酶存放2 h后失活35%,而固定化酶仅失活16%,说明反胶束固定化LDH具有良好的活力稳定性.

Study on the Enzymatic Kinetic Characterizations of LDH in CTAB-Pentanol Reversed Micelles

By CTAB-isooctane-pentanol reversed micelles system,LDH was immobilized.The affecting factors such as W0(W0=n(water)/n(CTAB)),concentration of CTAB and pentanol volume proportion for immobilization and enzymatic kinetic characterizations of free and immobilized LDH were investigated.The results showed that when W0 = 4.3,concentration of CTAB was 0.24mol/L and pentanol volume proportion was 25% respecively,LDH could best enter into reverse micelles.The optimum pH value of enzymatic reaction for free and immobilized LDH was both 8.8,the optimum temperature was 52℃and 30℃,the(Km) for lactate was 65 mmol/L and 48 mmol/L respectively.In 2 h at 25℃,the activities of LDH were lost 35% for free enzyme but 16% for immobilized enzyme,which indicated that the immobilized LDH in reversed micelles has good thermal stability.