Study On Separation And Purification Of S-adenosyl-L-methionine And Glutathione From The Yeast Cells

S-adenosyl-L-methionine (SAM-e, AdoMet or SAM) and glutathione (GSH) were two important molecules widely existed in various cells. The separation and purification of them as well as the preparation of stable SAM salt were studied.Firstly, a strong acid anion ion-exchange resin HZ001 was chosen to isolate GSH from the extract of spent yeast cell, and its capacity for GSH was 8.1mg/ml (wet resin). The separation process of SAM was performed in a fixed-bed ion-exchange column, and the operation conditions were optimized for the separation of GSH from the extract. The recovery of GSH reached 91%.Secondly, the ion-exchange separation process of SAM from the extract of yeast cell was investigated. Among the resins used, JK110 resin was the best one and its capacity for SAM was 172.8mg/g (dry resin) while GSH was hardly adsorbed. So GSH could be separated and purified by HZ001 resin consequently. The ion-exchange equilibrium, exchange velocity and dynamic column process of SAM on JK110 resin were investigated. The equilibrium isotherms were obtained at various pH values and temperatures and the related equilibrium models were examined. The ion-exchange kinetics of SAM+/H+ system based on JK110 resin was also discussed. And the rate-limiting step of the ion-exchange process was determined. A model of particle diffusion was proposed to describe the effects of pH, temperature and SAM concentration in the solution on the exchange velocity. By simulating experimental data with model equation, parameters were determined. In addition, the separation conditions of SAM in a fixed-bed ion-exchange column were optimized, and a recovery of 93% is obtained. After desorption, the eluate was concentrated and then crystallized with methanol. The white powder obtained was analyzed by HPLC and the purity was 95%. At the end, the preparation of stable SAM salt was studied and SAMe disulphate-p-toluenesulphonate was obtained. The purity of SAM product was over 98%.