Erythrocytes copper

Erythrocuprein, which contains about 60 wt % of the erythrocyte copper, hepatocuprein, and cerebrocuprein act as superoxide dismutases. Each contains two atoms of copper per molecule, having mol wt ca 34,000. The superoxide ion, O", and peroxide, two main toxic by-products of... 

P2. Pagliardi, E., Giangrandi, E., and Vinti, A., Erythrocyte copper in iron deficiency anaemia. Acta Haematol. 19, 231-240 (1958). 

For a long time erythrocuprein was thought to act exclusively as a copper-transporting protein. This was a very attractive conclusion since over 50% of the erythrocyte copper content is present in erythrocuprein (60). However, in the absence of any known function of a metalloprotein, it is always tempting to assign to it the role of storage or transport of the respective metal ions. For example, caeruloplasmin was considered to be the main copper-transporting protein in blood plasma. It subsequently turned out that this copper protein is a key enzyme in iron metabolism, responsible for the oxidation of Fe2+ to the Fe3+ bound in transferrin (130—132). 

Forman and Fridovich (1973) using an indirect assay whereby O2 was generated either by the action of xanthine oxidase on xanthine or by the mechanical infusion of potassium superoxide in tetrahydrofuran. The generated OJ was allowed to react with ferricytochrome c or with tetra-nitromethane and the product formation was monitored spectroscopically. Details of the two assays are given in Section 11.3. Addition of superoxide dismutase inhibits the formation of products. A rate constant of 2 X 10 M sec was determined for all three enzymes. This value agreed with the rate constant determined by pulse radiolysis for the copper/zinc enzyme (Klug-Roth et al., 1973 Fielden et al., 1974). The mechanism of action of the superoxide dismutases has been investigated by the technique of pulse radiolysis which is described in Section II.2. The bovine erythrocyte copper/zinc enzyme is the most studied form as far as the molecular and catalytic properties are concerned (Rotilio and Fielden,... 

Another direct assay method is based on decay kinetics of pulse generated O2 (Takahashi and Asada, 1981). Superoxide was produced within 10 msec by a flash of light through the excitation of flavin mononucleotide in the presence of A,A,A, A -tetramethylethylenedi-amine and oxygen. The kinetics of O2 decay in the presence and absence of enzyme were followed at 240 nm. The catalytic rate constant for bovine erythrocyte copper/zinc superoxide dismutase was found to be 1.75 x... 

The average concentration of copper in blood is 1.10 mg/1 in men and 1.23 mg/I in women. More than 90% of copper in the body is found in the blood plasma. The major copper-binding substance in blood plasma is monomeric glycometaUoprotein ceruloplasmin from a group of a2-globulins (132 kDa), which is composed of 1046 amino acids and contains about 7-8% of sugar components. Ceruloplasmin has a blue colour and in the normal state one molecule of ceruloplasmin contains six atoms of copper (at full saturation additional binding sites may be occupied by an additional two copper atoms). Blood plasma contains about 300 mg/1 of ceruloplasmin. In erythrocytes, copper occurs in another protein called erythrocuprein (31 kDa) and in the enzyme superoxide dismutase. 

Copper. AH human tissues contain copper. The highest amounts are found in the Hver, brain, heart, and kidney (102). In blood, plasma and erythrocytes contain almost equal amounts of copper, ie, ca 110 and 115 mg/100 mL, respectively. 

Water soluble protein with a relative molecular mass of ca. 32600, which particularly contains copper and zinc bound like chelate (ca. 4 gram atoms) and has superoxide-dismutase-activity. It is isolated from bovine liver or from hemolyzed, plasma free erythrocytes obtained from bovine blood. Purification by manyfold fractionated precipitation and solvolyse methods and definitive separation of the residual foreign proteins by denaturizing heating of the orgotein concentrate in buffer solution to ca. 65-70 C and gel filtration and/or dialysis. 

Red blood cells also contain sufficient acid phenylphospha-tase for mild hemolysis to cause false elevations. Therefore, inhibitors such as ethanol, formaldehyde, copper sulfate> and 1-tartrate have been used to inhibit selectively the enzyme of one or more tissues and enhance the specificity of the test (101). Ethanol is unsuitable because it inhibits the enzyme from erythrocytes and prostate simultaneously, and because it yields serum activities which correlate poorly with prostatic disease. Formaldehyde inhibits the erythrocytic enzyme and has been said to yield clinically satisfactory results. The copoper resistant acid phosphatase of serum is elevated by metastatic carcinoma of the breast, as well as by other metastatic cancers, and is also elevated by a wide variety of non-cancerous diseases. 

J.S. Valentine, M.W. Pantoliano, PJ. Mcdonnell, A.R. Burger, and S.J. Lippard, pH-dependent migration of copper(II) to the vacant zinc-binding site of zinc-free bovine erythrocyte superoxide dismutase. Proc. Natl. Acad. Sci. U.S.A. 76, 4245-4249 (1979). 

J.A. Fee and R.G. Briggs, Reconstitution of bovine erythrocyte superoxide dismutase. V. Preparation and properties of derivatives in which both zinc and copper sites contain copper. Biochim. Biophy. Acta. 400, 439 150 (1975). 

H. Markowitz, G.E. Cartwright, and M.M. Wintrobe, Copper metabolism. XXVII. Isolation and properties of an erythrocyte cuproprotein (erythrocuprein). J. Biol. Chem. 234, 40-45 (1959). 

In 1989, we showed [142] that the Fe2+(rutin)2 complex is a more effective inhibitor than rutin of asbestos-induced erythrocyte hemolysis and asbestos-stimulated oxygen radical production by rat peritoneal macrophages. Later on, to evaluate the mechanisms of antioxidant activities of iron rutin and copper-rutin complexes, we compared the effects of these complexes on iron-dependent liposomal and microsomal lipid peroxidation [165], It was found that the iron rutin complex was by two to three times a more efficient inhibitor of liposomal peroxidation than the copper-rutin complex, while the opposite tendency was observed in NADPH-dependent microsomal peroxidation. On the other hand, the copper rutin complex was much more effective than the iron rutin complex in the suppression of microsomal superoxide production, indicating that the copper rutin complex indeed acquired additional SOD-dismuting activity because superoxide is an initiator of NADPH-dependent... 

Iron-, copper-, and zinc complexes of rutin, dihydroquercetin, and green tea epicatechins were found to be much more efficient inhibitors than parent flavonoids of toxic effects of chrysotile asbestos fibers on peritoneal macrophages and erythrocytes [168], It was proposed that in this case the enhanced activity of metal-flavonoid complexes was increased by the absorption on chrysotile fibers. 

Bettger, W.J., D.J. Spry, K.A. Cockell, C.Y. Cho, and J.W. Hilton. 1987. The distribution of zinc and copper in plasma erythrocytes and erythrocyte membranes of rainbow trout (Salmo gairdneri). Comp. Biochem. Physiol. 87C 445-451. 

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