摘要
从不同来源的储粮样品中分离了4株灰绿曲霉、3株白曲霉,将培养后菌体破碎得到的粗酶液分别经硫酸铵盐析、SephadexG-200柱层析纯化得到过氧化氢酶.对分离酶的主要特性研究结果表明,这些过氧化氢酶的最适温度均为35℃左右,在水溶液中对热不稳定.酶催化适宜的pH范围为4～9,最适pH均在7 0左右,酶的Km值在33.3～41.7mmol/L范围,金属离子及化合物对酶活力的影响基本相同;1mmol/L浓度的Cu2+、Mg2+、Fe2+、Zn2+对酶活力有激活作用,1mmol/L浓度的巯基乙醇、Fe3+、Ca2+对酶活力有抑制作用,1mmol/L的NaN3、Hg2+可使酶完全失活.该特性研究为酶学方法测定储粮霉菌的应用奠定了基础.
4 strains of A.glaucus and 3 strains of A.candidus were isolated from the storage cereals.Each catalase was purified by ammonium sulfate fractionation precipitation,dialysis and Sephadex G-200 column chromatography respectively.The experiment result indicated that the catalases from A.glaucus and A.candidus had the same optimum temperature at about 35℃,but they were not heat-stable in water.They showed high enzyme activity at pH4.0～9.0,but the optimal pH was about 7.0.their Km is in 33.3～41.7 mmol/L.The enzymes can be activated by 1 mmol/L Cu2+,Mg2+,Fe2+,Zn2+,and be inhibited by 1 mmol/L Fe3+,Ca2+,and be inactivated by 1 mmol/L NaN3,Hg2+.
