关键词: 弹性蛋白酶, 纯化, 酶学性质, 地衣芽孢杆菌ZJUEL31410

Abstract: The fermentation supernatant (rich in elastase) of Bacillus licheniformis ZJUEL31410, a strain isolated from soil, was used as a crude enzyme solution, from which elastase was separated by (NH4)2SO4 segmentation precipitation and purified by Sephadex gel column chromatography. The enzymatic characteristics of purified elastase were measured. The specific activity of elastase could be increased to 120 U/mg through (NH4)2SO4 precipitation with 40%－70% saturation degree and continually increased to 292 U/mg after Sephadex gel column purification and the purification fold was 12.6. SDS-PAGE studies demonstrated that the enzyme had a molecular weight of 29.5 kD. The optimum reaction temperature and pH were 55 ℃ and 7.4, respectively, and the Michaelis constant Km was 9.67 mg/mL with elastin-Congo red as the substrate. Low concentrations of Ca2+and K+ could enhance elastase activity, while Mg2 +, Mn2 +, Zn2 +and Al3 + revealed an inhibition effect.

Key words: Bacillus licheniformis ZJUEL31410, elastase, purification, enzymatic properties