Takahashi K, Tamaura Y, Kodera Y, Mihama T, Saito Y, Inada Y
Biochem Biophys Res Commun. 1987 Jan 30;142(2):291-6. doi: 10.1016/0006-291x(87)90271-3.
Magnetic lipase (magnetite particles coated with polyethylene glycol-modified lipase) was prepared in two steps: Lipase was coupled with 2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine, activated PEG2, to obtain polyethylene glycol-modified lipase, PEG-lipase. The PEG-lipase was added to the solution of ferrous (Fe2+)- and ferric(Fe3+)-ions with the pH value adjusted to 8.0-8.5 to obtain magnetic lipase. The magnetic lipase was dispersed in organic solvents such as benzene and 1,1,1-trichloroethane with the particle size of 120 +/- 60 nm. The colloidal solution was very stable and no aggregation occurred even after 5 days. A high enzymic activity (11.6 mumol/min/mg protein) for lauryl laurate synthesis was observed in 1,1,1-trichloroethane. The magnetic lipase was readily recovered from the organic solvents in a magnetic field of 6000 Oe without loss of the enzymic activity.
磁性脂肪酶（涂有聚乙二醇修饰脂肪酶的磁铁矿颗粒）分两步制备：脂肪酶与2,4-双（O-甲氧基聚乙二醇）-6-氯-s-三嗪（活化聚乙二醇2）偶联，得到聚乙二醇修饰脂肪酶（PEG-脂肪酶）。将PEG-脂肪酶加入到pH值调至8.0 - 8.5的亚铁（Fe2+）和铁（Fe3+）离子溶液中，得到磁性脂肪酶。磁性脂肪酶分散在苯和1,1,1-三氯乙烷等有机溶剂中，粒径为120±60 nm。胶体溶液非常稳定，即使5天后也未发生聚集。在1,1,1-三氯乙烷中观察到月桂酸月桂酯合成的高酶活性（11.6 μmol/分钟/毫克蛋白质）。在6000奥斯特的磁场中，磁性脂肪酶很容易从有机溶剂中回收，且酶活性无损失。
