混合溶剂系统中固定化脂肪酶对酮基布洛芬的催化酯化反应

以硅藻土吸附的脂肪酶为催化剂,对外消旋酮基布洛芬[2-(3-苯甲酰苯基)丙酸]进行对映选择性酯化反应;考察了不同的脂肪酶制剂,固定化时所加缓冲液的体积与pH值,酰基受体(醇)的种类以及混合溶剂系统的组成等因素对酶活性的影响.结果表明,在所考察的7种脂肪酶中,以LipaseOF的酪化活性最高;用硅藻土吸附固定化酶时,缓冲溶液的最适pH为7.0左右,每克酶粉加1.0mL缓冲溶液为最佳;固定化酶催化酯化的活性比游离的脂肪酶高.在酮基布洛芬与不同酰基受体(醇)的酶促酯化反应中,以丙醇的反应速度为最快.在由一种主溶剂与一种助溶剂组成的混合溶剂系统中,酶促酯化的速度要比在单一的主溶剂或助溶剂系统中快.当以1gP值较大的环己烷或异辛烷等为主溶剂,甲苯为助溶剂时,脂肪酶催化酮基布洛芬酯化反应的活性最高.

Enantioselective Esterification of Ketoprofen by Immobilized Lipase in Mixed Solvent Systems

Enantioselective esterification of racemic ketoprofen[2 (3 benzoylphenyl) propionic acid] was carried out in organic solvents by using celite adsorbed lipase as the catalyst. Factors influencing the activity of the immobilized lipase had been investigated. Among the seven lipases examined, the esterification activity of Lipase OF(from Candida rugosa) was the highest; the activity of immobilized lipase was improved as compared with free lipase; the optimum volume of buffer(0.1 mol/L Na 2HPO 4 NaH 2PO 4, pH 7.0) for enzyme immobilization was 1 mL pergram lipase. Among the acyl receptors such as methanol, ethanol, n propanol, n butanol, n octanol, iso propanol and 2 ethylene chlorohydrin, n propanol was the best; In the mixed solvent system composed of a main solvent and a cosolvent, the esterification activity of lipase was higher than that in the single solvent system composed of the corresponding main solvent or cosolvent. The esterification activity of lipase was the highest when using cyclohexane or iso octane, both of which have high lg P values, as main solvents and toluene as cosolvent.