Slomczynska U, Zabrocki J, Kaczmarek K, Leplawy M T, Beusen D D, Marshall G R
Institute of Organic Chemistry, Politechnika, Lodz, Poland.
Biopolymers. 1992 Nov;32(11):1461-70. doi: 10.1002/bip.360321106.
We have used a combined chemical-enzymatic approach to facilitate the total synthesis of the 20-residue peptaibol, alamethicin. The 1-11 segment of alamethicin, having a C-terminal Gly, and the 12-20 segment, having an N-terminal Leu, were prepared by well-established chemical methods, and then coupled using papain to afford a 54% yield of alamethicin in straightforward fashion. In contrast to the reported chemical syntheses of alamethicin requiring side-chain protection at Glu,18 the papain-catalyzed coupling proceeded readily and selectively using a C-terminal segment having a free gamma-carboxyl group at this position. Several alamethicin partial sequences were obtained via enzymatic formation of the Gly11-Leu12 bond. The high efficiency of this route is illustrated by the enzymatic assembly of the 1-17 alamethicin fragment on a 400-mg scale in 62% yield. An alternative route to alamethicin through enzymatic formation of the Ala6-Gln7 bond was less successful because of a low yield in the final coupling.
我们采用了化学-酶促相结合的方法来促进20个残基的肽抗生素阿拉霉素的全合成。阿拉霉素的1-11片段（C端为甘氨酸）和12-20片段（N端为亮氨酸）通过成熟的化学方法制备，然后使用木瓜蛋白酶进行偶联，以直接的方式获得了54%产率的阿拉霉素。与报道的需要对谷氨酸18进行侧链保护的阿拉霉素化学合成方法不同，木瓜蛋白酶催化的偶联反应使用在此位置具有游离γ-羧基的C端片段即可轻松且选择性地进行。通过酶促形成甘氨酸11-亮氨酸12键获得了几个阿拉霉素部分序列。这条路线的高效性体现在以400毫克规模酶促组装1-17阿拉霉素片段时产率达到62%。通过酶促形成丙氨酸6-谷氨酰胺7键的另一条合成阿拉霉素的路线不太成功，因为最终偶联产率较低。
