Liver molybdenum

Of the mammalian enzymes, the sulphite oxidase of bovine liver has only recently been discovered to contain molybdenum (15). The better known molybdenum enzymes, xanthine oxidase from cows milk (31) and aldehyde oxidase from rabbit liver (16) are closely related to one another as they are to the xanthine dehydrogenases from chicken liver (17) and from bacteria (18). 

Xanthine dehydrogenase from chicken liver reacts readily with NAD as acceptor (77) while that from Micrococcus lactilyticus is inactive towards this, reacting instead with ferredoxin (18). Both enzymes react only slowly with oxygen. It seems reasonable to assume, however, that for each member of this group of enzymes, reducing substrates all react via molybdenum, as in milk xanthine oxidase. Presumably, different... 

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. 

Wildlife, 9 species From areas of high environmental molybdenum levels Liver 0.1-4 DW 20... 

Kume, S., A. Mukai, and M. Shibata. 1984. Effects of dietary copper and molybdenum levels on liver and kidney minerals in Holstein cattle. Japan. Jour. Zootech. Sci. 55 670-676. 

Requirements for trace elements during organ failure are not clearly defined. Manganese and copper should be restricted or withheld in patients with cholestatic liver disease. Chromium, molybdenum, and selenium should be restricted or withheld in patients with renal failure. 

Molybdenum Milk, milk products dried legumes or pulses liver and kidney grains Prosthetic group of enzymes aldehyde oxidase Xanthine oxidase Electron transfer chain enzymes... 

Robin, Turdus migratorlus, from molybdenum mine site Liver Kidney... 

Molybdenum is found primarily in the liver, kidneys, bone, skin and adrenal glands. 

One-electron reduction of chicken liver sulfite oxidase produces a species in which the molybdenum centre is Mo(V) and the b-type heme is low-spin Fe(III).90... 

The folding pattern of cytochrome b5 is also found in the complex heme protein flavocytochrome b2 from yeast (Chapter 15)133 and probably also in liver sulfite oxidase134,135 Both are 58-kDa peptides which can be cleaved by trypsin to 11-kDa fragments that have spectroscopic similarities and sequence homology with cytochrome b5. Sulfite oxidase also has a molybdenum center (Section H). The 100-residue N-terminal portion of flavocytochrome b2 has the cytochrome b5 folding pattern but the next 386 residues form an eight-stranded (a / P)8 barrel that binds a molecule of FMN.133,136 All of these proteins pass electrons to cytochrome c. In contrast, the folding of cytochrome... 

Long recognized as an essential element for the growth of plants, molybdenum has never been directly demonstrated as a necessary animal nutrient. Nevertheless, it is found in several enzymes of the human body, as well as in 30 or more additional enzymes of bacteria and plants.632 Aldehyde oxidases,633 xanthine oxidase of liver and the related xanthine dehydrogenase, catalyze the reactions of Eqs. 16-58 and 16-59 and contain molybdenum that is essential for catalytic activity. Xanthine oxidase also contains two Fe2S2 clusters and bound FAD. The enzymes can also... 

The first hint of an essential role of molybdenum in metabolism came from the discovery that animals raised on a diet deficient in molybdenum had decreased liver xanthine oxidase activity. There is no evidence that xanthine oxidase is essential for all life, but a human genetic deficiency of sulfite oxidase or of its molybdopterin coenzyme can be lethal.646,646a,b The conversion of molybdate into the molybdopterin cofactor in E. coli depends upon at least five genes.677 In Drosophila the addition of the cyanolyzable sulfur (Eq. 16-64) is the final step in formation of xanthine dehydrogenase.678 It is of interest that sulfur (S°) can be transferred from rhodanese (see Eq. 24-45), or from a related mercaptopyruvate sulfurtransferase679 into the desulfo form of xanthine oxidase to generate an active enzyme.680... 

Anemia can be induced in animals on a low copper diet, such as milk, and appears 10 be due to an impaired ability of the body to absorb iron. This anemia, however, is rare, because of the widespread occurence of copper in foods. In locations, such as Australia and lire Netherlands, diseases of cattle and sheep, involving diarrhea, anemia and nervous disorders, can be traced either to a lack of copper in the diet, or to excessive amounts of molybdenum, which inhibits the storage of copper in the liver. 

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