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KMID : 0377519820070020163
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Chung-Ang Journal of Medicine
1982 Volume.7 No. 2 p.163 ~ p.172
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Purification and Properties of Superoxide Dismutase from Human Term Placenta
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Moon Jin-Soo
Kwon Nyoun-Soo
Lee Keun-Bai
Lee Hi-Sung
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Abstract
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The distribution and some properties of superoxide dismutase of human term placenta have been studied. Human placenta was fractionated by differential centrifugation into mitochondrial and cytosolic fractions. The activity of superoxide dismutase was measures by the methodof McCord and Fridovich. Cytosolic superoxide dismutase was purified by ammonium sulfate precipitation, treatment with a chloroform-ethanol mixture, and DEAE-cellulose column chromatography. The results are summarized as follows; 1. Human term placenta contains two types of superoxide dismutase, one of which is localized in the mitochondria while the other is found in the cytosol. The mitochondrial superoxide dismutase was inactivated by treatment with a moxture of chloroform and ethanol whereas the cytosolic superoxide dismutase was not. 2. The activity of cytosolic and mitochondrial superoxide dismutase was found to be 7.44 units and 1.27 units per g of wet tissue, repectively. 3. The molecular weight of cytosolic superoxide dismutase was estimated to be about 33,000 by gel filtration. 4. The ultraviolet absorption spectrum of cytosolic enzyme indicates the lack of tryptophan. The spectrum of the enzyme in the uitraviolet region was similar to that of phenylalanine. 5. Purified cytosolic superoxide dismutase contains 2Cu^2+ and 2Zn^2+ per molecule. This enzyme was found to be similar to the other cupro-zinc superoxide dismutase which have been isolated from diverse eukaryotes. 6. Cyanide at 0.5 mM and 5.0 mM inhibits the activity of cytosolic superoxide dismutase 31% and 98%, respectively, but mitochondrial superoxide dismutase was not inhibited by this compound.
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