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Thermodynamically controlled synthesis of amide bonds catalyzed by highly organic solvent-resistant penicillin acylase derivatives

机译：高度耐有机溶剂的青霉素酰化酶衍生物催化的热力学控制合成酰胺键

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摘要

A study of various direct condensations between different amines, having very high pK values, and unmodified acyl donors has been performed. This has been possible by the use of a very stable PGA derivative. First, it has been found that the higher the cosolvent concentration, the higher the pK of the acyl donor and thus the higher the yield. Therefore, these high concentrations of cosolvents seem to be a requisite for certain enzymatic condensations. Using ethanolamine and 2-hydroxy-2-phenylethylamine as nucleophiles and phenyl acetic acid as the acyl donor, the increase in the diglyme concentration from 50 to 90% (v/v) permitted improvement of not only the yield (reaching values higher than 99% in both cases) but also the reaction rates (by 360- or 3-fold, respectively). However, even when using PGA preparations stabilized by multipoint covalent attachment, it was not possible to obtain these results by inactivation of the enzyme derivative. Thus, in the protection of the octylamine with phenylacetic acid in 90% diglyme, the enzymatic activity was more than 20-fold higher using the hydrophilized derivative than the glyoxyl PGA, which allowed us to obtain a yield higher than 99%. Thus, the use of hydrophilized derivatives that are very stable even in the presence of high concentrations of organic solvents opens new opportunities in the use of PGA in organic chemistry.
机译：已经对具有非常高的pK值的不同胺与未修饰的酰基供体之间的各种直接缩合进行了研究。这可以通过使用非常稳定的PGA衍生物来实现。首先，已发现助溶剂浓度越高，酰基供体的pK越高，因此产率越高。因此，这些高浓度的助溶剂似乎是某些酶促缩合的必要条件。使用乙醇胺和2-羟基-2-苯基乙胺作为亲核试剂，使用苯基乙酸作为酰基供体，将二甘醇二甲醚浓度从50％（v / v）增加到不仅可以提高收率（达到高于99的值）在两种情况下均为％），但反应速率（分别为360倍或3倍）。但是，即使使用通过多点共价连接稳定化的PGA制剂，也无法通过酶衍生物的失活获得这些结果。因此，在90％的二甘醇二甲醚中用苯乙酸保护辛胺时，使用亲水化的衍生物的酶活性比乙醛基PGA高20倍以上，这使我们获得的收率高于99％。因此，即使在高浓度有机溶剂存在下也非常稳定的亲水化衍生物的使用为有机化学中使用PGA开辟了新的机会。

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