A study of the copper-binding proteins in liver and kidney tissue of neonatal normal and mottled mutant mice

Abstract

The Cu2+-binding proteins from liver and kidney tissue of 7--8-day-old brindled (Mobr) mice and their normal littermates were compared. (1) Separation over Bio-Gel P-10 showed that the differences in the Cu2+ content of mutant tissues were largely associated with a low-molecular-weight protein fraction (mol.wt. 14 500). (2) Further purification of this low-molecular-weight fraction by anion-exchange chromatography revealed four subfractions. The Cu2+ content of each subfraction reflected the Cu2+ status of the tissue of origin; the Cu2+ contents of the mutant kidney subfractions were elevated and those of the mutant liver were depressed compared with normal. In contrast, the protein contents of the subfractions were less variable and did not reflect the differing Cu2+ contents. (3) Amino acid analysis of the four subfractions from CuCl2-treated mutant and normal animals revealed clos similarities. The proteins showed high glycine, glutamic acid, serine, alanine and lysine contents and a rather variable cysteine content. Differences were apparent in the normal liver subfractions, which showed a higher cysteine content and lower glutamic acid content than did either the mutant liver or normal and mutant kidney subfractions. These observations, together with the recorded presence of aromatic amino acids, indicated that these proteins are not thioneins.

Metal-dependent properties of metallothionein. Replacement in vitro of zinc in zinc-thionein with copper

“…The changes of chromatographic properties of metallothionein induced by replacement of Zn2+ with Cu2+ are probably related to the oxidation of cysteine residues (intramolecular oxidation of metallothionein) by Cu2+. Multi-forms of coppercontaining metallothionein (Port & Hunt, 1979;Riordan & Richards, 1980;Ryden & Deutsch, 1978;Saylor et al, 1980) may be explained by the intramolecular oxidation observed in the present study. The intramolecular-oxidation products of metallothionein were eluted slower than the native molecule on an SW-gel column, suggesting that the Retention time The two isoproteins of cadmium-thionein were isolated by preparative column chromatography on an SW 3000-gel column (22.5 mm x 600 mm, with a pre-column of 22.5mm x 100mm) by elution with 50mM-Tris/HCl buffer, pH8.0 at 250C, at a flow rate of 3.5ml/min.…”

Congenital Copper Deficiency: Copper Therapy and Dopamine‐β‐Hydroxylase Activity in the Mottled (Brindled) Mouse

“…The X-linked mottled (Mo) spontaneous mutant of the mouse, Mus musculus, has been described as an animal model of this disorder (Danks et al, 1972;Hunt, 1974). The precise biochemical relationship bet ween the disorders in mouse and man has been outlined (Danks et al, 1972;Danks, 1977;Camakaris et al, 1979;Port and Hunt, 1979;van den Hamer, 1979, 1980;Nooijen et al, 1981) and may be related to disturbed Cu homeostasis, involving both impaired absorption and altered tissue distribution (Danks, 1977;Horn et al, 1978). The abnormal Cu distribution is suggested to be the result of increased amounts of a cysteine-rich 10,000 dalton Cu binding protein (Labadie et al, 1981).…”

The effect of copper supplementation on the concentration of copper in the brain of the brindled mouse

“…Experiments with this mouse model have greatly benefited the study of Menkes' disease (Prins & Van den Hamer, 1979, 1980Camakaris et al, 1979;Port & Hunt, 1979).…”