摘要
从常现青霉麸曲中抽提的β-半乳糖苷酶(E.C.32。1.23,亦称乳糖酶)粗制品,经两次硫酸铵盐析沉淀和DEAE纤维素柱层析,纯度提高了近55倍,纯化酶的最适反应温度为62～65℃,最适反应pH为4.0。于pH2.2～8.0放置过夜,酶活性基本稳定。以邻硝基苯酚β-半乳糖苷(ONPG)为底物时该酶的K_m为2.06 mmol/L。Cu^(++),Fe^(++)和N-溴代琥珀酰亚胺(NBS)对酶活性有明显的抑制作用,Mn^(++)为该酶的激活剂。
β-Galactosidase (lactase) from a strain of Penicillum frequentans was purifiedby ammonium sulfate fractionation and chromatography on DEAE-cellulose. Theproperties of the partially purified enzyme were studied. The optimal pH was 4.0and optimal temperature was around 62℃. The enzyme kept overnight at roomtemperature was stable over a pH range of 2.2~8.0. It was stable at 55℃ for 15minutes, but inactivaed at 63℃. The K_m value was 2.06 mmol/L for ONPG. Cu^(++),Fe^(++) and N-bromosuccinimide markedly inhibited its activity, while Mn^(++) enhan-ted it.
出处
《复旦学报（自然科学版）》
CAS
CSCD
北大核心
1990年第1期79-84,共6页
Journal of Fudan University：Natural Science
关键词
常现青霉
半乳糖苷酶
纯化
性质
β-galactosidase, purifications, characters
Penicillium frequentans.
