A better synthetic route to β-carboxyaspartic acid (Asa) was achieved through condensation of sodium dibenzyl malonate and benzyl 2-bromoacetate as an alternative to two steps in the method of Koch etal. Catalytic hydrogenation at 5 atm pressure in a shaken stainless steel vessel removed protecting carbobenzyloxy groups. Asa was purified on a cation exchange column. An extract of E. coli was found to catalyse the decarboxylation of Asa in a doubly coupled assay designed to be specific for produced aspartic acid. Evidence for enzymatic decarboxylation includes complete loss of activity on boiling and progressive loss of activity on repeated freeze–thawing of the extract. Keywords: decarboxylation, β-carboxyaspartic acid, Asa decarboxylase.
通过
钠二
苯甲酸二苄酯和苄基2-
溴乙酸酯的缩合反应,成功实现了β-羧基
天冬氨酸(Asa)的更好合成路线,作为Koch等人方法中两个步骤的替代方法。在摇晃的不锈钢容器中,5大气压的催化加氢去除了保护性的羧苄氧基。Asa在阳离子交换柱上被纯化。通过特定于产生的
天冬氨酸的双重偶联测定,发现大肠杆菌
提取物能催化Asa的脱羧反应。酶促脱羧的证据包括在沸腾时完全失去活性以及在重复冻融
提取物时逐渐失去活性。关键词:脱羧反应,β-羧基
天冬氨酸,Asa脱羧酶。