嗜冷枯草芽孢杆菌低温脂肪酶纯化与酶学性质研究

Purification and Enzymatic Characters of Low-temperature Lipase from Bacillus phychrophilus

摘要:

从筛选出的产低温脂肪酶的菌株发酵液中，经硫铵沉淀、疏水色谱和阴离子交换色谱纯化得到电泳纯酶。酶的最适作用温度为25℃，0℃以下仍可保持25%左右的相对酶活；在pH5.8～8.8的范围内有较高活力，其最适作用pH为7.8；对热很敏感，在60℃保温30min活性即全部丧失，具有典型的低温脂肪酶特征；酶催化不需要金属离子的参与，结构中可能含有二硫键。在25℃，pH8.0测得酶水解反应的K_m值为2.65×10^-5mol/L，V_max值为5.21mmol/(L·min)。

Abstract:

This study involves purification of a wild low-temperature lipase from a strain of Bacillus phychrophilus and analysis of its enzymatic characters. Electrophoretic pure enzyme on the SDS-PAGE was obtained through ammonium sulfate precipitation, phenyl superpose hydrophobic chromatography and Q FF anion-exchange chromatography.The optimum temperature of the enzyme is 25℃, which still has 25% relative lipase activity at 0℃. The activity of the lipase almost completely lost after incubation at 60℃ for 30 min. Lipase activity is independent of divalent cation. And the structure of this lipase may contain disulfide bond. The K_m and V_max of lipase under pH8.0 and 25℃ were 2.65×10^-5mol/L and 5.21mmol/(L·min) respectively.