【摘要】 从茶花粉中提纯的超氧化物歧化酶(SOD)为Cu,Zn-SOD,分子量为69.5kD,亚基分子量为34.7kD,是由相同亚基组成的二聚体。等电聚焦电泳测得等电点为pH4.1,二甲氨基丹磺酰氯法确定其N-末端氨基酸为Gly,圆二色谱法测得α螺旋含量为21.8%。性质研究表明该蛋白在pH5～10范围内基本稳定,在5～35℃内保温30min酶活性基本保持不变;化学试剂KCN、H2O2、EDTA、巯基乙醇、SDS对酶活性完全抑止,4mol/L的尿素不影响酶活性。茶花粉SOD用EDTA去除金属离子后重新加入Cu2+、Zn2+恢复至天然活性,而加入Mn2+、Mg2+只能部分恢复活性。更多还原

【Abstract】 Superoxide dismutase from camellia pollen was purified to homogeneity and assayed to be Cu, Zn-SOD accordingto its specific sensitivities to hydrogen peroxide, cyanogens potassium and chloroform-alcohol. The molecular weights of the SOD and its subunit were 69.5kD and 34.7kD, respectively. Isoelectric point analysis indicated that it was an acidic protein whose isoelectric point was pH4.1. The N-terminal amino acid of the enzyme was identified to be Gly by DNS- Cl method. Its content of α-Helix was also assayed to be approximately 21.8% according to the result of circular dichroism (CD) spectra. The effects of pH, temperature, chemical reagents and metal ions on SOD were studied respectively in its molecular stability experiments. Results showed that the optimum temperature and pH of the enzyme were 25℃ and 6.5 respectively. It lost its activity entirely when the pH was higher than 10, and its activity was also highly inhibited when KCN, H2O2, SDS and β- mercaptoethanol existed, but 4mol/L carbamide had no effect on it. The activity of the SOD whose metal ions were driven out by EDTA recovered totally after combining with Cu2+, Zn2+ but only partly recovered after combing with Mn2+, Mg2+.更多还原