摘要
采用70%乙醇对凝乳酶进行粗提,回收率为52.65%。采用DE-52和SephadexG-75柱进行纯化,经冷冻干燥成酶粉,其活力1813.74U/mg,回收率为11.25%。该酶的最适反应pH为5.7,在pH5～7.5范围酶活力保持稳定;最适反应温度45℃,60℃保持20min,酶完全失活。Ca2+、Fe2+、Mg2+、Cu2+、Zn2+、Al3+对该酶的活力有不同程度的促进作用,其中以Al3+和Ca2+的促进作用最显著,Na+和K+对该酶的活力有抑制作用。通过SDS-PAGE测定,该酶的分子质量约35kDa。
Crude chymosin was extracted by 75% ethanol precipitation,resulted in 52.65% recovery of total chymosin.Then using DE-52 and Sephadex G-75 to purify,and using a freeze dryer to desiccate,1 813.74 SU/g activity and 11.25% recovery of chymosin were obtained.The optimum pH and temperature for chymosin were 5.7 and 45 ℃ recpectively,and it is stable at the pH range of 5.0～7.5.Chymosin was completely inactivated at 60 ℃ for 20min.Ca2＋,Fe2＋,Mg2＋,Cu2＋,Zn2＋,Al3＋ showed obvious stimulation on the chymosin activity,Ca2＋ and Al3＋ showed outstanding stimulation effect on the chymosin activity.However,Na＋ and K＋ could inhibit the activity of chymosin.The molecular weight of chymosin was about 35 kDa tested by SDS-PAGE.
出处
《中国食品学报》
EI
CAS
CSCD
北大核心
2011年第2期53-59,共7页
Journal of Chinese Institute Of Food Science and Technology
基金
国家农转基金项目(2009GB2C220412)
国家自然基金项目(30972130)
关键词
根霉
凝乳酶
分离纯化
酶学性质
Rhizopus stp.
chymosin
isolation and purification
enzymological characteristics.
