Eisenberg M A, Stoner G L
J Bacteriol. 1971 Dec;108(3):1135-40. doi: 10.1128/jb.108.3.1135-1140.1971.
Resting cells of Escherichia coli strain D302(bioD302) can synthesize 7,8-diaminopelargonic acid from 7-keto-8-aminopelargonic acid. The product of this aminotransferase reaction has been identified by paper chromatography and electrophoresis. Glucose enhances the vitamer yield twofold. Of the 19 amino acids tested as amino donors, only methionine proved to be significantly stimulatory. In cell-free extracts, however, methionine was completely inactive unless both adenosine triphosphate (ATP) and Mg(2+) were present. S-Adenosyl-l-methionine (SAM) was about 10 times more effective than methionine, ATP, and Mg(2+). The optimal conditions for the reaction were determined, and substrate inhibition was found for 7-keto-8-aminopelargonic acid. It has been possible to eliminate certain impurities as amino donors in the commercial preparation of SAM and those that may arise in enzymatic reactions in which SAM is a substrate. The direct participation of SAM in the aminotransferase reaction seems a likely possibility.
大肠杆菌D302（bioD302）的静止细胞能够从7-酮-8-氨基壬酸合成7,8-二氨基壬酸。该转氨酶反应的产物已通过纸色谱法和电泳法进行了鉴定。葡萄糖可使维生素原产量提高两倍。在作为氨基供体测试的19种氨基酸中，只有蛋氨酸被证明具有显著的刺激作用。然而，在无细胞提取物中，除非同时存在三磷酸腺苷（ATP）和镁离子（Mg(2+)），否则蛋氨酸完全无活性。S-腺苷-L-蛋氨酸（SAM）的效果比蛋氨酸、ATP和Mg(2+)大约高10倍。确定了反应的最佳条件，并发现7-酮-8-氨基壬酸存在底物抑制作用。在SAM的商业制备中以及在SAM作为底物的酶促反应中可能产生的某些杂质作为氨基供体已被去除。SAM直接参与转氨酶反应似乎很有可能。
