Preparation and Properties of Sodium Alginate-Immobilized S-Adenosylmethionine Synthetase

The immobilization of S-adenosylmethionine(SAM) synthetase by embedding in sodium alginate was studied and properties of the immobilized enzyme were investigated.The results showed the optimal immobilization conditions were as follows:mass fraction of sodium alginate was 3%,mass fraction of calcium chloride was 4%,SAM synthetase amount was 75 mg,immobilization time was 30 min.Under the optimum conditions,the activity recovery rate of the immobilized enzyme reached 42%.The immobilized enzyme showed a good thermal stability compared with the free enzyme.After incubated at 50 ℃ for 5 h,the immobilized enzyme maintained 69% of the original activity while the free enzyme lost all.The immobilized enzyme showed a good stability in alkaline solution,it still kept more than 84% of the original activity when incubated in the buffer solution with pH value of 7.5~9.0 at 4 ℃ for 10 h.When employed to synthesize SAM,the immobilized enzyme maintained 82% of the original activity after consecutive use for 5 times.