小黑麦中1,5-二磷酸核酮糖羧化酶的纯化与特性分析
Purification and characterization of ribulose-1,5-bisphosphate carboxylase from triticale.
作者信息
Khan M A, Dixit A, Upadhyaya K C
机构信息
School of Life Sciences, Jawaharlal Nehru University, New Delhi.
出版信息
Indian J Biochem Biophys. 1994 Apr;31(2):121-6.
Ribulose-1,5-bisphosphate carboxylase has been isolated from a synthetic cereal triticale and purified using a newly developed rapid procedure involving precipitation with ammonium sulphate (35-55% saturation), DEAE-cellulose (DE-52) chromatography and filtration through Sepharose CL-68. Molecular weights of the enzyme subunits are 15.5 and 52 kDa which corresponds to 540 kDa for the hexadecameric holoenzyme. Isoelectric focussing showed that the enzyme has a pI of 4.2. Various kinetic constants determined under aerobic conditions are: Km (CO2), 118 microM; Km (RuBP), 220 microM (at 20 mM NaHCO3) and Vmax, 690 nmole CO2 fixed/mg enzyme/min.
1,5-二磷酸核酮糖羧化酶已从人工合成谷物小黑麦中分离出来，并采用一种新开发的快速方法进行纯化，该方法包括硫酸铵沉淀（饱和度35-55%）、DEAE-纤维素（DE-52）色谱法和通过Sepharose CL-68过滤。该酶亚基的分子量分别为15.5 kDa和52 kDa，十六聚体全酶的分子量为540 kDa。等电聚焦显示该酶的等电点为4.2。在有氧条件下测定的各种动力学常数如下：Km（CO2）为118 μM；Km（RuBP）为220 μM（在20 mM NaHCO3条件下），Vmax为690纳摩尔CO2固定/毫克酶/分钟。
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