The molybdenum nitrogenase, present in a diverse group of bacteria and archea, is the major contributor to biological nitrogen fixation. The nitrogenase active site contains an iron-molybdenum cofactor (FeMo-co) composed of 7Fe, 9S, 1Mo, one unidentified light atom, and homocitrate. The nifQ gene was known to be involved in the incorporation of molybdenum into nitrogenase. Here we show direct b...

A brief survey is given of the thermochemistry of a number of silicon-containing substances that are of interest in modern technology. Among those discussed are: silicalite (SiO2), silicon disulfide (SiS2), the crystalline and vitreous forms of silicon diselenide (SiSen), silicon sesquitelluride (Si2Te3), silicon nitride (Si3N4), and vanadium disilicide (VSi2).

The reaction of 2,4-bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide (Woollins' Reagent, WR) with phenylalkylcyanamides (RR'NC[triple bond, length as m-dash]N, R = PhCH2CH2, R' = CH3 and R = PhCH2CH2CH2, R' = H) in refluxing toluene led to novel heterocyclic selenazadiphospholaminediselenides and (43% and 42% yields), the latter being hydrolyzed to the unusual zwitterionic carbamidoyl(pheny...

Background: Molybden, as a vital and essential micronutrient is directly involved in the metabolism of other elements including carbon, sulfur, and nitrogen. Molybdenum alone is not biologically active unless it binds to specific cofactors. Except for the bacterial nitrogenase, which contains molybdenum-Iron complex, molybdenum cofactor (Moco) is considered as the bioactive component placed in ...

the reduction mechanism of molybdenum-methyl thymol blue (mtb)-chlorate system has been investigated in water on a mercury electrode. as this system is very sensitive for ultratrace determination of molybdenum, the actual mechanism involved was studied. electrochemical techniques, including dc tast polarography and cyclic voltammetry were employed. it is shown that, the cathodic wave of molybde...

Selenium and molybdenum are essential trace elements. Considering the characteristics of selenium and molybdenum, our research had the following purposes for both elements: Considering Se the uptake of selenium was investigatein maize and sunflower seedling, moreover the different effect of two selenium species (selenite and selenite) for the examined plants (a monocotyledon (maize, Zea mays L....

A molybdenum cofactor which is capable of reconstituting demolybdosulfite oxidase purified from livers of tungstentreated rats has been identified in rat liver and various organisms. Reconstitution with the rat liver cofactor is directly proportional to cofactor and demolybdoenzyme concentrations and proceeds most efficiently in 0.01 M potassium phosphate buffer, pH 7.4. The activation process ...

1. The effect ofdietary molybdenum on the growth rate and also on ascorbic acid metabolism in rats was studied. An excess of dietary molybdenum resulted in growth retardation and loss of weight. Tolerance to molybdenum was affected by the nature ofthe molybdenum salt administered. 2. Molybdenum ingestion altered certain aspects of ascorbic acid metabolism in rats. The conversion ofD-glucuronola...

Molybdenum, applied in vivo, restored the damage from low temperature with winter wheat (Triticum aestivum, var "Sadovo 1") grown on acid soil and, in addition, sharply increased productivity (G Salcheva, D Georgieva, 1982; G Salcheva et al., 1977, 1979). Two fractions with molybdenum-cofactor activity in seeds were detected. One of them has a molecular weight of about 230 kilodaltons correspon...

Molybdenum reduction to molybdenum blue by microbes is a potential bioremediation tool for molybdenum pollution. A previous work using cyanide as a respiratory inhibitor has shown that the site of molybdenum reduction in Enterobacter cloacae strain 48 is at the electron transport pathway. In the present work, several respiratory inhibitors together with cyanide were used to reinvestigate the si...