Albumin copper

The availability of copper in the body is somewhat different from that of iron. Copper in the Mood serum is bound in caeruloplasmin, Excessive dietary copper is predominately carried by serum albumin. Serum albumin copper is in the equilibrium with low molecular mass complexes of amino acids or small peptides. Unfortunately, the concentration of such complexes is below the detection limit. Regardless of the... 

Albumlngehalt, m. albumin content, albuminisieren, v.t. albuminize. Albuminisienmg, /. albuminization. Albumin-kupfer, m. copper albuminate, -stoff, m. albuminous substance, protein, -sub-stanz, f. albuminoid substance, -urie, /. albuminuria. 

Another important function of albumin is its ability to bind various ligands. These include free fatty acids (FFA), calcium, certain steroid hormones, bilirubin, and some of the plasma tryptophan. In addition, albumin appears to play an important role in transport of copper in the human body (see below). A vatiety of drugs, including sulfonamides, penicilhn G, dicumarol, and aspirin, are bound to albumin this finding has important pharmacologic implications. 

Copper is an essential trace element. It is required in the diet because it is the metal cofactor for a variety of enzymes (see Table 50—5). Copper accepts and donates electrons and is involved in reactions involving dismu-tation, hydroxylation, and oxygenation. However, excess copper can cause problems because it can oxidize proteins and hpids, bind to nucleic acids, and enhance the production of free radicals. It is thus important to have mechanisms that will maintain the amount of copper in the body within normal hmits. The body of the normal adult contains about 100 mg of copper, located mostly in bone, liver, kidney, and muscle. The daily intake of copper is about 2—A mg, with about 50% being absorbed in the stomach and upper small intestine and the remainder excreted in the feces. Copper is carried to the liver bound to albumin, taken up by liver cells, and part of it is excreted in the bile. Copper also leaves the liver attached to ceruloplasmin, which is synthesized in that organ. 

Ceruloplasmin contains substantial amounts of copper, but albumin appears to be more important with regard to its transport. Both Wilson disease and Menkes disease, which reflect abnormahties of copper metabohsm, have been found to be due to mutations in genes encoding copper-binding P-type ATPases. 

Albumin, the major protein of human plasma (reference interval 535-760 / M), has the properties of copper... 

Lovstad, R.A. (1984). Catecholamine stimulation of copper-dependent haemolysis protective action of superoxide dismutase, catalase, hydroxyl radical scavengers and scrum proteins (ceruloplasmin, albumin and apotransferrin). Acta Pharmacol. Toxicol. 54, 340-345. 

Caeruloplasmin (Cp) is an acute phase glycoprotein with a copper transport function. At least 90% of total plasma copper is bound to Cp with the remaining 10% associated with albumin, histidine and small peptides. Lipid peroxidation requires the presence of trace amounts of transition metals and the copper-containing active site of Cp endows it with antioxidant capacity... 

Chromium has proved effective in counteracting the deleterious effects of cadmium in rats and of vanadium in chickens. High mortality rates and testicular atrophy occurred in rats subjected to an intraperitoneal injection of cadmium salts however, pretreatment with chromium ameliorated these effects (Stacey et al. 1983). The Cr-Cd relationship is not simple. In some cases, cadmium is known to suppress adverse effects induced in Chinese hamster (Cricetus spp.) ovary cells by Cr (Shimada et al. 1998). In southwestern Sweden, there was an 80% decline in chromium burdens in liver of the moose (Alces alces) between 1982 and 1992 from 0.21 to 0.07 mg Cr/kg FW (Frank et al. 1994). During this same period in this locale, moose experienced an unknown disease caused by a secondary copper deficiency due to elevated molybdenum levels as well as chromium deficiency and trace element imbalance (Frank et al. 1994). In chickens (Gallus sp.), 10 mg/kg of dietary chromium counteracted adverse effects on albumin metabolism and egg shell quality induced by 10 mg/kg of vanadium salts (Jensen and Maurice 1980). Additional research on the beneficial aspects of chromium in living resources appears warranted, especially where the organism is subjected to complex mixtures containing chromium and other potentially toxic heavy metals. 

Many copper(II) complexes, including Cu(DIPS)2 (DIPS = diisopro-pylsalicylate), Cu(salicylate)2, and Cu(Gly-His-Lys), are also active in superoxide dismutation (437, 438), but their use in vivo is limited by dissociation of Cu(II) and binding to natural ligands such as albumin (439). In contrast, the activity of Fe-93 is not affected by albumin (439, 440). 

Contrary to popular belief, ceruloplasmin5, the principal copper-containing protein in plasma, ceruloplasmin, is not involved in copper transport. This is clearly underlined by the clinical observation that patients with aceruloplasminaemia (i.e. lacking ceruloplasmin in their blood) have perfectly normal copper metabolism and homeostasis. Copper is transported in plasma mostly by serum albumin with smaller amounts bound to low-molecular weight ligands like histidine. Likewise zinc is mostly transported in plasma bound to proteins (albumin and ot2-macroglobulin). 

Despite the positive effects of optimal levels of copper, deleterious effects may occur if a threshold level is exceeded. Wilson s disease (hepatolenticularic degeneration) is one of the diseases linked to the excess of copper in the body. It results from a dysfunction of the copper transmission process, which occurs due to a lack of suitable enzyme to catalyze the process of copper deletion from detached bonds with albumins and binding to ceruloplasma. The condition leads to neuron degradation, liver cirrhosis, and occurrence of colorful rings on the cornea (DiDonato and Sarkar, 1997). 

Recent publications signal the continued interest in the function of this protein. It has been called a stress enzyme, involved in influenza virus infection (Tomas and Toparceanu, 1986). An explanation for Wilson s disease in terms of a genetic defect resulting in failure to convert from a neonatal (i.e., low) level of ceruloplasmin and copper to a normal adult level has been reported (Srai et al., 1986). Tissue specificity for the binding of ceruloplasmin to membranes was demonstrated in a study investigating the possible role of ceruloplasmin-specific receptors in the transfer of copper from ceruloplasmin to other copper-containing proteins (Orena et al, 1986). Ceruloplasmin has been shown to be effective in transferring copper to Cu,Zn-SOD in culture (Dameron and Harris, 1987), as has copper albumin. In view of the variable content of copper in this protein, it is not clear which copper is transferred. 

AAS is used in a number of limit tests for metallic impurities, e.g. magnesium and strontium in calcium acetate palladium in carbenicillin sodium and lead in bismuth subgallate. It is also used to assay metals in a number of other preparations zinc in zinc insulin suspension and tetracosactrin zinc injection copper and iron in ascorbic acid zinc in acetylcysteine lead in bismuthsubcarbonate silver in cisplatinum lead in oxyprenolol aluminium in albumin solution and calcium, magnesium, mercury and zinc in water used for diluting haemodialysis solutions. 

Albumin is a major transport facilitator of hydrophobic compounds which would otherwise disrupt cellular membranes. These compounds include free fatty acids and bilirubin as well as hormones such as cortisol, aldosterone, and thyroxine when these materials have exceeded the capacity of proteins normally associated with them. Albumin also binds ions, including toxic heavy metals and metals such as copper and zinc which are essential for normal physiological functioning but may be toxic in quantities in excess of their binding capacity for their carrier proteins. Binding of protons is the basis for the buffering capacity of albumin. 

Copper is bound by albumin or histidine after uptake in the gut, and transported in this form to the liver, where it is transferred to ceruloplasmin. Some 95% of copper in human serum is... 

Ortmans I, Moucheron C, Kirsch-De Mesmaeker A (1998) Ru(ll) polypyridine complexes with a high oxidation power. Comparison between their photoelectrochemisty with transparent SnC>2 and their photochemistry with desoxyribonucleic acids. Coord Chem Rev 168 233-271 Ozawa T, Ueda J, Flanaki A (1993) Copper(ll)-albumin complex can activate hydrogen peroxide in the presence of biological reductants first ESR evidence for the formation of hydroxyl radical. Biochem Mol Biol Int 29 247-253... 

---