Dameron C T, Harris E D
Department of Biochemistry and Biophysics, Texas A & M University, College Station 77843-2128.
Biochem J. 1987 Dec 15;248(3):663-8. doi: 10.1042/bj2480663.
Cu2Zn2-superoxide dismutase (CuZn-SOD) was purified from chicken liver. The liver enzyme had a subunit Mr of 16900 and contained equimolar amounts of copper and zinc [0.26% (w/w) for each]. Aortic CuZn-SOD had the same Mr as estimated by gel filtration and cross-reacted with antibodies to the liver enzyme. Both enzymes were inhibited by 1.0 mM-NaCN. Within 24-72 h after hatching, total SOD activity in aorta rose 3-fold over the day-1 level and stayed elevated for 10 days. With low dietary copper, the total SOD activity rose as before, but then decayed progressively to non-detectable levels in 10 days. Both the cyanide-sensitive (CuZn-SOD) and insensitive (mangano-SOD) activities fell, but not at the same rate. When the 10-day-old deficient chicks were injected with 0.5 mumol of CuSO4 intraperitoneally, SOD activity in aorta was restored to control levels in about 8 h. Despite non-measurable SOD activity in aorta, extracts from the 15-day-old-deficient-chick tissue contained as much, or slightly more, immunoreactive CuZn-SOD protein as age-matched control tissue. The data show clearly that dietary copper regulates SOD activity in the aortas of young developing animals. They further suggest that a copper deficiency suppresses CuZn-SOD activity without inhibiting synthesis or accumulation of the CuZn protein in this tissue.
铜锌超氧化物歧化酶（CuZn-SOD）从鸡肝中纯化得到。肝脏中的这种酶亚基分子量为16900，且铜和锌的含量等摩尔[每种均为0.26%（w/w）]。主动脉中的CuZn-SOD经凝胶过滤估算具有相同的分子量，并且能与针对肝脏酶的抗体发生交叉反应。两种酶都受到1.0 mM-NaCN的抑制。在孵化后24至72小时内，主动脉中的总超氧化物歧化酶活性比第1天的水平升高了3倍，并在10天内保持升高。在低铜饮食条件下，总超氧化物歧化酶活性如之前一样升高，但随后在10天内逐渐下降至检测不到的水平。对氰化物敏感的（CuZn-SOD）和不敏感的（锰超氧化物歧化酶）活性均下降，但下降速率不同。当给10日龄的缺乏铜的雏鸡腹腔注射0.5 μmol硫酸铜时，主动脉中的超氧化物歧化酶活性在约8小时内恢复到对照水平。尽管主动脉中无法检测到超氧化物歧化酶活性，但15日龄缺乏铜的雏鸡组织提取物中含有的免疫反应性CuZn-SOD蛋白与年龄匹配的对照组织一样多，或略多。数据清楚地表明，饮食中的铜调节幼龄发育动物主动脉中的超氧化物歧化酶活性。它们还进一步表明，铜缺乏会抑制CuZn-SOD活性，但不会抑制该组织中CuZn蛋白的合成或积累。
