水果超氧物歧化酶活性及性质

采用ＮＢＴ光化还原法对２２种水果进行ＳＯＤ活性测定，结果表明，新鲜水果富含ＳＯＤ，其中菠萝和山楂ＳＯＤ活性最高，克鲜重酶活性超过３００单位，其次是葡萄、枣、桑椹，克鲜重酶活性在２８８—２２４单位之间．酶的比活以山楂最高，毫克蛋白质达２２９．５单位．８种供试水果果皮中ＳＯＤ活性均明显高于果肉．这２２种水果中至少有９种不同的ＳＯＤ同工酶，其中４种同工酶在多数水果中出现．试验表明，水果ＳＯＤ活性在贮存期内均呈下降趋势．菠萝ＳＯＤ的热稳定性、酸碱稳定性高于西瓜ＳＯＤ．水果普遍具有Ｃｕ·Ｚｎ—ＳＯＤ和Ｍｎ—ＳＯＤ，本研究还发现菠萝、蕉柑和枣具有Ｆｅ—ＳＯＤ．

The Activity and Some Properties of Superoxide Dismutase in Fruits

The results of the assay of SOD activity of 22 fruits with NBT photochemical reduction demonstrated that: The fresh fruits are all rich with SOD, but the pineapples and hawthorn have the highest activity of these enzymes and there not less than 300 units per fresh weight gram, then the grape, jujube and mulberry, their activity are 224- 228 units per fresh weight gram.The highest relative activity of enzyme was discovered in hawthorn, which attains to 229. 5 units per miligram protein. In eight fruits assayed, obviously the activity of the SOD in fruit flesh is higher than in fruit peel. At least, there are 9 types of SOD isozymes finded in 22 kinds of frait, the 4 types from the isozymes are widespread in most fruit species. The activity of SOD is tending to decline in preserved stage of all the fruits. The heat and acid-basestabilityies of the SOD in pineapple are higher than in waterpselon. Any fruits commonly contains Cu - Zn-SOD and Mn-SOD, moreover we find the pineapple,tangevine (Jiaogan) and jujube have Fe-SOD as well in our experiments.