Organically bound copper isolation

The chromatographic procedure intially investigated was reverse-phase liquid chromatography (RPLC) using Cig-bonded silica gel. This technique has been used previously for the preconcentration of trace metals from seawater prior to analysis by atomic absorption spectrophotometry (23, 24) and for the isolation of organically bound copper from seawater (4). These methods were modified and adapted for automation. 

Isolation of organically bound copper was accomplished by using the method of Mills et al. (4). The same preconcentrator configuration employed for total metals was used, and the Cjg-SEP-PAK cartridges were cleaned in the manner just described. Untreated seawater was passed through the column, a Milli-Q water wash followed, and elution was by a 50 50 water-methanol mixture. The column was then prepared for another run by cleaning with water-methanol and Milli-Q water. 

Topaquinone (TPQ). Both bacteria and eukaryotes contain amine oxidases that utilize bound copper ions and 02 as electron acceptors and form an aldehyde, NH3, and H202. The presence of an organic cofactor was suggested by the absorption spectra which was variously attributed to pyridoxal phosphate or PQQ. However, isolation from the active site of bovine serum... 

Foetal and neonatal livers contain exceptionally high levels of copper compared to the adult organ. Thus, the livers of new-born rats contain as much as 20 times the level of copper and zinc metallothionein as that found in 70-day-old rats.1150 Again, a metallothionein from foetal bovine liver contained eight copper and two zinc atoms per molecule of protein.1151 These proteins can only be isolated with difficulty under oxygen-free conditions. It appears then that large amounts of copper (and zinc) are stored in the liver bound to metallothionein, and are mobilized as required for enzyme synthesis after birth. 

The metal composition of native MTs depends on the natural source and/or on the previous exposure of the organism to metals. The inducible MT-1 and MT-2 isoforms isolated from adult and fetal human livers contain mainly zinc, while those isolated from adult human kidney contain mainly cadmium with some copper or zinc. It may be noted that in higher organisms MTs are the sole proteins in which cadmium accumulates naturally. Both mammalian tissue specific forms MT-3 and MT-4 contain zinc and copper. In contrast to MTs from mammalian sources, in which zinc, cadmium, and copper can be simultaneously bound, yeast (53 aa) and fungal (25 aa) MTs contain exclusively copper. Specific binding of cadmium or copper to different tissue specific MT forms in vivo has been encoimtered in the snail Helix pomatia. ... 

Most cadmium in urine is bound to metallothionein. This protein occurs in the organism as at least four genetic variants. The two major forms, I and II, are ubiquitous in most organs, particularly in the liver and kidney, and also in the brain. Metallothionein isolated from adult or fetal human livers contained mainly zinc and cooper, whereas that from human kidneys contained zinc, copper, and cadmium. 

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