Rare Ginsenosdie C-K: From Enzymatic Transformation To Synthetic Biology Design

Rare ginsenoside C-K is a non-natural ginsenoside, which is the mainultimate-metabolic product of ginsenosides by intestinal microbial. Rare ginsenosideC-K can be absorbed directly and play a major biological activity role in human body.Our laboratory has established an enzymatic catalysis reaction system thattransformed ginsenoside Rb1into rare ginsenoside C-K by inexpensive crude snailasein optimized reaction conditions that103mg of rare ginsenoside has been preparedfrom300mg ginsenoside catalyzed by48mg crude snailase at pH value of4.4,temperature of46.40℃, catalysis time of15h. A continuous operation of enzymatictransformation ginsenoside Rb1into rare ginsenoside C-K based on the optimizedreaction system was carried out. Then an advisable scale-up of enzymatictransformation ginsenoside Rb1into rare ginsenoside C-K had achieved. At last asynthetic biological device for the preparation of rare ginsenoside C-K was designed.1. Continuous operation of enzymatic transformation ginsenoside Rb1into rare ginsenoside C-K. According to the optimal conditions of enzymatictransformation ginsenoside Rb1into rare ginsenoside C-K by snailase. Acontinuous operation of enzymatic transformation ginsenoside Rb1into rareginsenoside C-K had designed after we found out time required of each step inthe enzymatic hydrolysis. In one mouth2675mg of rare ginsenoside C-K wasprepared through14batches28groups optimized enzymatic hydrolysis, whichapproached the yield of single optimized enzymatic hydrolysis. The result ofcontinuous operation enzymatic hydrolysis showed that the reaction system ofenzymatic transformation ginsenoside Rb1into rare ginsenoside C-K bysnailase is stable and highly repeatability.2. The scale-up experiment of the preparation of rare ginsenoside C-Kbased on ginsenoside Rb1catalyzed by crude snailase was performed. In onebatch,1675mg of rare ginsenoside C-K has been prepared from6gginsenoside Rb1catalyzed by960mg snailase. The cost of the preparation of 1mg rare ginsenoside C-K decreased from2.0869CNY to1.3547CNY. Thetime consumed by the preparation of100mg rare ginsenoside C-K reduced to0.44d from4d.3. A synthetic biological device for the preparation of rare ginsenosideC-K was designed based on four catalysis steps of squalene by squaleneepoxidase, dammarenediol-II synthase, cytochrome monooxygenase P450andginsenoside glycosyltransferase, respectively.