月桂酰氯修饰羊血超氧化物歧化酶工艺优化及酶学性质

以羊血为材料获得超氧化物歧化酶（superoxide dismutase，SOD）酶液，采用月桂酰氯修饰SOD，在修饰温度、修饰时间、月桂酰氯添加量和丙酮添加量的单因素试验基础上，通过正交试验优化工艺参数，并比较修饰酶与天然酶的酶学性质。结果表明：10 mL酶比活力为4 348.6 U/mg的SOD样液在修饰温度60 ℃、修饰时间30 min、月桂酰氯用量0.1 mL、丙酮添加量为酶液体积的1.5 倍条件下充分反应，所得修饰酶活力最强；修饰酶热稳定性、pH值耐受性、半衰期等均优于天然酶。月桂酰氯可用于修饰性能较优的羊血超氧化物歧化酶。

Optimized Preparation and Enzymatic Characterization of Lauroyl Chloride Modified SOD from Sheep Blood

The process condition for modifying SOD from sheep blood by lauroyl chloride was explored. Four experimentalparameters including reaction temperature, reaction time and the amounts of lauroyl chloride and acetone added to SODsolution were investigated by one-factor-at-a-time experiments and optimized by orthogonal array design. The highestenzyme activity was observed for SOD with a specific activity of 4 348.6 U/mg in a 10 mL aqueous solution when modifiedby reaction with 0.1 mL of lauroyl chloride and 15 mL of acetone for 30 minutes at 60 ℃. The modified SOD exhibitedimproved heat stability, pH tolerance and half-life compared to the intact one. Therefore, lauroyl chloride can be used tomodify sheep blood SOD for better enzymatic performance.