壳聚糖固定化羊血超氧化物歧化酶工艺条件优化及酶学性质比较研究

Optimization of Process Conditions for Chitosan-immobilized SOD from Sheep Blood and Its Enzymatic Characteristics

以羊血为材料获得超氧化物歧化酶(SOD)酶液,采用壳聚糖进行SOD固定化,对壳聚糖用量、戊二醛体积分数、反应时间及pH值对SOD固定化的影响进行研究,通过正交试验优化工艺参数,并比较固定化酶与天然酶的酶学性质。结果表明:10mL比活力为5219.3U/mg的SOD样液与0.25g用体积分数0.7%戊二醛活化的壳聚糖在pH5.6的条件下充分反应2h,所得的固定化酶的活力最强;固定化SOD比天然SOD热稳定性提高了65.2%,耐酸碱性提高了48.4%,Km值为0.18mmol/L。因此,壳聚糖可用于制备性能较优的固定化羊血超氧化物歧化酶。

The process conditions for immobilizing SOD from sheep blood by chitosan were explored. Chitosan dosage, glutaraldehyde concentration, reaction time and pH were optimized by orthogonal array design and a comparative evaluation of enzymatic properties was made between free and immobilized SOD. The immobilization conditions were optimized as following： enzyme activity of 5219.3 U/mg, chitosan dosage of 0.25 g, glutaraldehyde concentration of 0.7%, reaction time of 2 h and pH 5.6. Under the optimal process conditions, the highest activity of immobilized enzyme was obtained, and the thermal stability was increased by 65.2% when compared with natural SOD. Meanwhile, the resistance to acid and alkali demonstrated an increase of 48.4%, and Km was 0.18 mmol/L. Chitosan is useful to prepare high-performance immobilized SOD from sheep blood.