Copper complexes blood plasma

Mixed donor ligands. Thermodynamic parameters have been evaluated for the interaction of asparaginate with Fe2+ in aqueous solution at 25°C. On the basis of the results it is calculated that quite a large proportion of asparaginate in blood plasma may be complexed to iron(u) as well as to the expected copper(n).93 1.10-Phenanthro-line /V-oxide (phenNO) forms the complex [Fe(phenN0)3](C104)2 in which the ligands chelate by N- and O-donor atoms.96... 

May P. M., Linder P. W., and Williams D. R. (1977) Computer simulation of metal-ion equilibria in biofluids models for the low-molecular-weight complex distribution of calciu-m(II), magnesium(II), manganese(II), iron(III), copper(II), zinc(II), and lead(II) ions in human blood plasma. J. Chem. Soc. Dalton Trans. 588—595. 

Much of the copper in the plasma (60-95%) is bound to ceruloplasmin. The complex of copper and cenjloplasmir is assembled and secreted by the liver. A small fraction of plasma copper, under 7%, is weakly bound to albumin and to free amino acids, especially histidine, threonine, and glutamine. The copper bound to serum albumin is associated with a histidine residue near the amino terminus of the protein. The copper in red blood cells is bound to superoxide dismutase. 

Chilvers, D.C., Dawson, J.B.. Bahregni-Toosi, M.H. and Hodgkinson. A. (1984). Identification and Determination of Copper- and Zinc-Protein Complexes in Blood Plasma after Separation DEAE Sepharose C1-6B. Analyst, 109,871. 

Plasma copper exists in two forms 5% is loosely bound to albumin, and the remainder exists in the form of copper complexes. Copper forms ionic bonds with either an imidazole or a carboxyl group of the amino acid of albumin. Loosely bound copper reacts readily with dithiocarbamate, and therefore has been called the directly reacting copper. It is generally assumed but not established that the albumin that binds this copper plays an important role in transporting copper in the blood. 

In the blood plasma of mammals there is present a -pseudo-globulin called transferrin or siderophilin, and which at a definite point in its molecule forms an iron complex. This protein, whose molecular weight is in the region of 90,000, makes up about 3% by weight of the plasma proteins. The iron is complexed by it in the ferric form and only in the presence of COg. When the level of iron in the plasma is at its normal value, which in man is 129y/100 ml., the transferrin is saturated to the extent of 30% of the maximum amount of iron which it can carry. The same protein can also fix copper. 

Copper is also necessary for the efficient utilisation of iron and for the biosynthesis of some physiologically important compounds, such as the enzyme ceruloplasmin, which is produced in Hver cells and acts in the blood plasma as the main Cu compound, but it is not involved in copper transport to the target organs. Plasma copper is transported primarily bound to albumin and partly in the form of complexes with low molecular weight ligands, such as histidine. Ceruloplasmin also has the catalytic activity of ferro oxidase, which means that it catalyses the oxidation of Fe " " ions absorbed in the blood plasma to Fe + ions, thus allowing fixation of iron in the transferrin molecule. Copper deficiency, therefore, is similar to iron deficiency and leads to anaemia. 

Minoia, C., Sabbioni, E., Apostoli, P., Pietra, R.. Pozzoli, L, Gallorini, M., Nicolaou, G.. Alessio, L., and Capodaglio, E. (1990). Trace element reference values in tissues from inhabitants of the european community I. A study of 46 elements in urine, blood and serum of Italian subjects, Sci. Total Environ., 25.89-105 Olsen. A.D., and Hamlin, W.B. (1968). Serum copper and zinc by atomic absorption spectrophotometry. Atom. Absorpt. Newsl., Z, 69-71 Plantz, M.R., Fritz, J.S., Smith, F.G., and Houk, R.S. (1989). Separation of trace metal complexes for samples of high salt content by inductively coupled plasma mass spectrometry, Anal. Chem., 1,149-153... 

---