Arsenate inhibition

Minor additions of arsenic (0.02—0.5%) to copper (qv) and copper alloys (qv) raise the recrystaUization temperature and improve corrosion resistance. In some brass alloys, small amounts of arsenic inhibit de2incification (22), and minimise season cracking. 

The antiproliferative effects of arsenic are well documented. In vitro both divalent and pentavalent arsenicals inhibit murine [28] and bovine [18] phytohemaglutinin (PHA)-stimulated lymphoproliferation at concentrations of > 3 pM. Lymph node cells from arsenic treated, FTTC-sensitized mice displayed reduced lymphoproliferation in response to Con A, suggesting that the mechanism of antigen processing/presentation may be altered by arsenic exposure, inhibiting T-cell responsiveness [29], However, in vivo... 

Composition 70% copper, 29% zinc, 1% tin, and 0.03% arsenic. It has good corrosion resistance, especially in sea water. Arsenic inhibits the loss of zinc from the alloy. It is used for tubing applications in condensers, preheaters, evaporators, and heat exchangers which contact salt water, oil, steam, and other liquids below 500°F (260°C). 

If a soap is added to a lead hydrogen arsenate-hydrated ferric oxide mixture considerable damage and leaf drop is caused, especially if the soap contains a strong base, as in the case of commercial potash fish-oil soap or potassium oleate. Laboratory tests show that more soluble arsenic is formed than with a soap of a weak base such as triethanolamine oleate.7 The addition of cryolite to an arsenate inhibits the formation of soluble arsenic 8 fluosilicates cause decomposition. These fluorine... 

Agren 112) and Engstrom 113) isolated serine phosphate from mammalian alkaline phosphatase that had been incubated with inorganic phosphate in acid pH (<6). Engstrom 114) and Schwartz and Lipmann 35) later obtained similar results with E. coli alkaline phosphatase. They found that a large percentage of the enzyme is phosphorylated, that compounds like glucose 6-phosphate and sodium arsenate inhibit... 

In 1933, Klein discovered that sodium arsenate inhibits the action of the nucleotidase" of intestinal mucosa. Consequently, Klein and Thannhauser were enabled to hydrolyze thymus nucleic acid by means of intestinal desoxyribonucleinase without subsequent dephosphorylation of the liberated nucleotides. Making use, also, of Klein s discovery of the deaminase-inhibiting activity of silver ions, they were successful in isolating the adenine nucleotide. Hence the phosphodesoxyribosyl nucleotides of adenine, guanine, thymine, and cytosine were isolated and characterized. 

S Lin, LM Del Razo, M Styblo, C Wang, WR Cullen, DJ Thomas. Arsenicals inhibit thioredoxin reductase in cultured rat hepatocytes. Chem Res Toxicol 14 ... 

A.3.2 and As Hyperfine Interactions to the Phosphate- and Arsenate-Inhibited Mo(v) Species... 

K2CO3 plus AS2O3 Arsenic inhibits 500-1,000 ppmv Low... 

Pulmonary alveolar macrophages lavaged from As(V)-exposed male Sprague-Dawley rats showed significant increases in 02 production and in basal release of TNF-a, while As(III) did not induce significant alterations (Lantz et al. 1995). Neither arsenical inhibited prostaglandin Ej production. 

It was at this state of knowledge that an incidental observation with extracts of C. kluy-veri led to a development which played a significant role in elucidating the mechanism of CoA action. It was observed that arsenate inhibited the ability of extracts to catalyze the oxidation of butyrate, as well as the reduction of acetyl-P and acetate to butyrate. The inhibition was ultimately explained by the fact that arsenate stimulated the enzymic hydrolysis of acetyl-P [reaction (18)]. By analogy to the postulated role of arsenate in the hydrolysis of glucose-l-P by sucrose phosphorylase,< > it was proposed that the arsenolysis of acetyl-P could be the result of a reversible transfer of the acetyl moiety to an acetyl acceptor, x , catalyzed by a phosphotransacetylase [reaction (21)]. 

Brass alloys containing less than 15% zinc are resistant to dealloying. Alloying elements such as tin and arsenic inhibit this type of corrosion. 

Vacuum filters and centrifuges are satisfactory, although in small installations filters appear to be more economical. A favorable characteristic of the G-V process is that the arsenic inhibited alkali carbonate solution is only mildly corrosive, and relatively inert towards carbon steel, thus eliminating the need for using expensive alloy steel equipment. 

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