Regulation by copper

Figure 8.17 Copper-trafficking pathways within a mammalian cell. Regulation by copper deficiency (arrows connected by dotted lines) or overload (arrows connected by sobd lines) as currently understood. (From Bertinato and L Abbe, 2004. Copyright 2004, with permission from Elsevier.)...

The Department of Transportation requires labelling of aH shipments of amines commensurate with the associated hazards. Amine shipments are regulated by the Coast Guard, the DOT, and the International Air Transport Association. AHphatic amines are stored satisfactorily ia carboa steel and stainless steel, but are corrosive to copper, alumiaum, ziac, and their aHoys. 

Lead and copper are regulated by a Treatment Technique that requires systems to control the corrosiveness of their water. If more than 10% of tap water samples exceed the action level, water systems must take additional steps. For copper, the action level is 1.3 mg/L, and for lead is 0.015 mg/L. 

In mammals, as in yeast, several different metallothionein isoforms are known, each with a particular tissue distribution (Vasak and Hasler, 2000). Their synthesis is regulated at the level of transcription not only by copper (as well as the other divalent metal ions cadmium, mercury and zinc) but also by hormones, notably steroid hormones, that affect cellular differentiation. Intracellular copper accumulates in metallothionein in copper overload diseases, such as Wilson s disease, forming two distinct molecular forms one with 12 Cu(I) equivalents bound, in which all 20 thiolate ligands of the protein participate in metal binding the other with eight Cu(I)/ metallothionein a molecules, with between 12-14 cysteines involved in Cu(I) coordination (Pountney et ah, 1994). Although the role of specific metallothionein isoforms in zinc homeostasis and apoptosis is established, its primary function in copper metabolism remains enigmatic (Vasak and Hasler, 2000). 

The success of bis(oxazoline)-copper(II) catalyzed Diels-Alder reactions involving acryloylimides as dienophiles has been extended to the Michael reaction, Eqs. 204 and 205. The observed enantiofacial discrimination in the Diels-Alder reactions was expected to translate well to Michael reactions involving enolsilanes as nucleophiles. Indeed, fumarate-derived imides afford Michael adducts of enolsilanes in high enantioselectivity (240). Diastereoselectivity in these reactions may be regulated by judicious choice of thioester and enolsilane geometry to provide either diastereomer in high selectivity (>99 1 syn or 95 5 anti). 

Sunda, W. G. and Huntsman, S. A. (1995). Regulation of copper concentration in the oceanic nutricline by phytoplankton uptake and regeneration cycles, Limnol. Oceanogr., 40, 132-137. 

The copper bar (a) had a circular enlargement at. one end in which there were five holes the central one (F) contd mercury in which the bulb of a thermometer was immersed a small copper tube, contg 0.1 g of pulverized explosive to be tested, was placed in each of the other holes. The bar was supported on a stand and was heated by means of burners placed underneath it. The rate of heating could be regulated by moving the burners. The expl sample in tube (b) exploded first, then in (c) and (d) and finally (e). The... 

Arsenic is a by-product of the smelting of copper, lead, and zinc ores. It has been shown to produce acute and chronic toxic effects, with the trivalent (3+) form as the most toxic. Arsenic has been classified in the EPA s Group A (human carcinogen), and it is regulated by the U.S. government. 

The high resolution drift tube is fabricated from a six-inch diameter steel tube divided into three sections separated by ceramic breaks. The field in the interior is maintained by copper beryllium drift guard rings, connected to each other by a resistor chain. In Jarrold s apparatus [36] the ion exit hole has a diameter of 0.13 mm. The drift tube temperature is controlled by jackets around each section and by a recirculator with non-conducting temperature regulated fluorocarbon fluids. 

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