Copper associated protein

In 15 of 15 cases of primary biliary cirrhosis including early cases with minimal pathology, and in 5 of 5 cases of Wilson s disease, Elmes et al. (1989) found copper-associated protein. Metallothionein distribution was abnormal in most copper-associated protein-positive livers. Necrotic hepato-cytes were intensely metallothionein-positive and in Wilson s disease had a characteristic appearance. 

While foetal human livers showed periportal and staining, livers of children over 6 months of age patchy mid-zone copper-associated protein and showed no copper-associated protein or lipofuscin lipofuscin granules, together with strong diffuse cy- granules, and minimal or no metallothionein im-toplasmic and nuclear metallothionein immuno- munostaining (Fuller et al. 1990). 

Guarascio, P. Yentis, F. Cevikbas, U. Portmann, B. Williams, R. Value of copper-associated protein in diagnostic assessment of liver biopsy. J. Clin. Pathol. 1983, 36, 18-23. 

Yeast cytochrome oxidase is composed of probably seven subunits shown by gel electrophoresis to have molecular weights of about 40,000 27,300 25,000 13,800 13,000 10,200 and 9500. " Studies with protein synthesis inhibitors have demonstrated that both the cytoplasmic and mitochondrial systems contribute to the complex.Immunological studies by Kraml and Mahler have shown that cytoplasmic petite mutant cells contain the copper-associated protein of the complex, demonstrating the cytoplasmic origin of this component. Studies on the mitochondrial products have shown that the three proteins of highest molecular weight in the complex are mitochondrially synthesized and account for about half of the protein, by weight, of the cytochrome oxidase complex. 

Samuelsson (1960) observed that most of the natural copper associated with the cream phase can be removed by washing with water and that the actual fat globule membrane proteins contain approximately 4%o of the total natural copper content. Nevertheless, the value represents the highest concentration of copper per gram of protein in the milk system. Koops (1969) stated that although the amount of natu-... 

The biochemical importance of flavin coenzymes ap-pears to be their versatility in mediating a variety of redox processes, including electron transfer and the activation of molecular oxygen for oxygenation reactions. An especially important manifestation of their redox versatility is their ability to serve as the switch point from the two-electron processes, which predominate in cytosolic carbon metabo-lism, to the one-electron transfer processes, which predomi-nate in membrane-associated terminal electron-transfer pathways. In mammalian cells, for example, the end products of the aerobic metabolism of glucose are C02 and NADH (see chapter 13). The terminal electron-transfer pathway is a membrane-bound system of cytochromes, nonheme iron proteins, and copper-heme proteins—all one-electron acceptors that transfer electrons ultimately to 02 to produce H20 and NAD+ with the concomitant production of ATP from ADP and P . The interaction of NADH with this pathway is mediated by NADH dehydrogenase, a flavoprotein that couples the two-electron oxidation of NADH with the one-electron reductive processes of the membrane. 

Basu, P. Katterle, B. Andersson, K. K. Dalton, H. The membrane-associated form of methane mono-oxygenase from Methylococcus capsulatus (Bath) is a copper/iron protein. Biochem. J. 2003, 369(2), 417 127. 

Copper is an essential trace metal which is a component of a wide range of intracellular metalloen/ymes. including cytochrome oxidase, superoxide dismutase. tyrosinase, dopamine hydroxylase and lysyl oxidase. Most of the copper in plasma is associated w-ith the specific copper-binding protein, caeruloplasmin. 

Enzymes often need for their activity the presence of a non-protein portion, which may be closely combined with the protein, in which case it is called a prosthetic group, or more loosely associated, in which case it is a coenzyme. Certain metals may be combined with the enzyme such as copper in ascorbic oxidase and selenium in glutathione peroxidase. Often the presence of other metals in solution, such as magnesium, are necessary for the action of particular enzymes. 

Ceruloplasmin Binds Copper, Low Levels of This Plasma Protein Are Associated With Wilson Disease... 

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