仙人掌超氧化物歧化酶的纯化及其部分性质研究

10 0 0g仙人掌茎经匀浆、硫酸铵分级沉淀、SephadexG - 75凝胶层析和DEAE - 5 2离子交换层析 3个步骤 ,将仙人掌SOD纯化到SDS -PAGE均一纯 ,得白色粉状SOD 0 8985g ,比活 910U/mg,活力回收 4 3 1% ,纯化倍数 76。该酶相对分子质量 37 1kD ,H2 O2 和KCN的抑制实验结果表明为Cu、Zn -SOD。该酶的最大紫外吸收在 2 75nm处。 5 0℃保温 15 0min ,SOD的活性不变 ,在pH =5 0～ 9 0时SOD有较好的稳定性

Purification and Some Properties of Superoxide Dismutase from Cactus

Superoxide dismutase(SOD) from cactus(Opuntia ficus-indica Mill) was separated and purified through pulping, ammonium sulfate precipitation and column chromatography with Sephadex G-75 gel filtration and DEAE-52 ion exchange. SDS-PAGE demonstrated its homogeneity.0 8985 g purified SOD(white power)can be obtained from 1000 g stem of cactus.The specific activity is 910 U/mg,and the molecular weight of the enzyme is about 37,100 daltons.The enzyme is a copper/zinc superoxide dismutase as assayed by its sensitivity to inhibitors KCN and H 2O 2.Its maximum UV absorption is at 275 nm.The SOD from cactus has good heat(50 ℃,150 min)and acid base stability in pH 5 0-9 0 (25 ℃, 3 h),in which the activity of SOD does not decline.