Regulation of aortic CuZn-superoxide dismutase with copper. Effects in vivo.
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.
Department of Biochemistry and Biophysics, Texas A & M University, College Station 77843-2128.
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Dameron
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Harris
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D002645:Chickens; D003300:Copper / Q000494:pharmacology*; D019327:Copper Sulfate; D004789:Enzyme Activation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D008099:Liver / Q000201:enzymology; D008297:Male; D013482:Superoxide Dismutase / Q000378:metabolism*
D003300:Copper; D013482:Superoxide Dismutase; D019327:Copper Sulfate