Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
Bioorg Med Chem Lett. 2011 May 15;21(10):2934-6. doi: 10.1016/j.bmcl.2011.03.059. Epub 2011 Mar 21.
Acylation of Pseudomonas cepacia lipase with Pyromellitic dianhydride to modify 72% of total amino groups was carried out. Different organic solvents were screened for precipitation of modified lipase. It was found that 1,2-dimethoxyethane was the best precipitant which precipitated 97% protein and complete activity. PCMC (protein coated microcrystals), CLPCMC (crosslinked protein coated microcrystals), EPROS (enzyme precipitated and rinsed with organic solvents) and pH tuned preparations of modified and unmodified lipase were prepared and used for carrying out transesterification reaction with n-octane and dimethyl formamide (DMF) as reaction medium. In n-octane, among all the preparations, CLPCMC of modified lipase gave highest rate (1970 nmol min(-1)mg(-1)) as compared to unmodified pH tuned lipase (128 nmol min(-1) mg(-1)). In DMF, with both 1% (v/v) and 5% (v/v) water content, CLPCMC showed highest initial rate of 0.72 and 7.2 nmol min(-1) mg(-1), respectively. Unmodified pH tuned lipase showed no activity at all in DMF with both 1% and 5% (v/v) water content.
用均苯四酸二酐对假单胞菌脂肪酶进行酰化，将总氨基基团的 72%进行修饰。筛选了不同的有机溶剂用于沉淀修饰的脂肪酶。结果发现，1,2-二甲氧基乙烷是最佳沉淀剂，可沉淀 97%的蛋白质和全部活性。制备了 PCMC（蛋白包被微晶体）、CLPCMC（交联蛋白包被微晶体）、EPROS（有机溶剂沉淀和冲洗的酶）以及修饰和未修饰脂肪酶的 pH 调节制剂，并用于以正辛烷和二甲基甲酰胺（DMF）为反应介质进行酯交换反应。在正辛烷中，在所有制剂中，与未修饰的 pH 调节脂肪酶（128 nmol min(-1)mg(-1)）相比，修饰的 CLPCMC 脂肪酶的反应速率最高（1970 nmol min(-1)mg(-1)）。在含有 1%（v/v）和 5%（v/v）水的 DMF 中，CLPCMC 表现出最高的初始反应速率，分别为 0.72 和 7.2 nmol min(-1)mg(-1)。在含有 1%和 5%（v/v）水的 DMF 中，未修饰的 pH 调节脂肪酶均没有活性。
