Oxidation of benzoin with anchored vanadyl and
... carried out in the absence of catalyst, was very
slow and low yields of benzil were obtained
even when the reaction was allowed to proceed
for a longer time (up to 32 h). Experiments
were carried out using (i) the organic polymer
without ligand and metal complex and (ii) the
organic polymer function ...
A structural comparison of molybdenum cofactor
... families , namely the DMSO reductase, xanthine
oxidase, sul¢te oxidase, and AOR families. Within
each family, sequence similarities are obvious, while
no signi¢cant homologies can be detected between
members of di¡erent families. This classi¢cation represents a unifying approach in terms of the ...
Nitrate Reductases: Structure, Functions, and Effect of Stress Factors
... been supposed recently that only high-potential clusters
are able, for thermodynamic reasons, to transfer electrons,
whereas the role of the other two clusters is still unknown.
Subunit α (104-150 kD) coded by the narG gene
contains the [4Fe-4S] cluster and molybdenum cofactor,
just on which the nit ...
Substrate orientation and the origin of catalytic power in xanthine
... the reaction (in this case, through to formation of
the LMoIVO(SH)(OR) intermediate) decreased by
two orders of magnitude from 1.97 × 106 M-1s-1 to
1.34 × 104 M-1s-1. At face value, the effect on kred and
Kd is such that the interaction between Glu 232 and
substrate provides some 3 kcal/mol of free ...
Reaction of niobium with water
... procedure yields 98% pure niobium oxide in one phase and a 99.5% pure
tantalum oxide in another.
After conversion to the oxide, metallic tantalum can be made by reduction with
sodium or carbon. Electrolysis of molten fluorides is also used.
Molybdenum Complexes with Amino Acids as
... solution of Mo(V)chloride (0.2722 g, 1mmol), NaOH 0.1M was added to adjust the pH. The ligand solution of
Glutamic acid then was added (3mmol). The resulting mixture was stirred under reflux for 1h and 80°C. The
precipitate product was collected by Buchner filtration, washed with water, and dried in ...
... • At least 25 selenoproteins have been identified, but the metabolic functions
have been identified for only about one-half of them
Trace Minerals - Pure Encapsulations
... Cellular Function: Many minerals are important enzyme
cofactors for numerous processes, including cellular
energy production and the synthesis of hormones,
neurotransmitters and DNA. This formula provides these
trace minerals in a balanced combination, without macro
minerals, to promote optimal bioa ...
Molybdenum, Molybdenum in Drinking-water
... out by the International Programme on Chemical Safety, in its Environmental Health
Criteria monographs and Concise International Chemical Assessment Documents, the
International Agency for Research on Cancer, the Joint FAO/WHO Meetings on
Pesticide Residues and the Joint FAO/WHO Expert Committee on ...
... Catalytic experiments
The Mo-compounds are tested as catalysts in the air oxidation
... marginal lands during the national ploughing-up campaign. I was told to produce effects of all possible nutritional disorders in
any chosen crop using sand culture on an
unprecedented scale. Being young, inexperienced, and unaware that my senior
predecessor had departed at the prospect, I
saw no pro ...
Molybdenum is a chemical element with symbol Mo and atomic number 42. The name is from Neo-Latin molybdaenum, from Ancient Greek Μόλυβδος molybdos, meaning lead, since its ores were confused with lead ores. Molybdenum minerals have been known throughout history, but the element was discovered (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele. The metal was first isolated in 1781 by Peter Jacob Hjelm.Molybdenum does not occur naturally as a free metal on Earth, but rather in various oxidation states in minerals.The free element, which is a silvery metal with a gray cast, has the sixth-highest melting point of any element. It readily forms hard, stable carbides in alloys, and for this reason most of world production of the element (about 80%) is in making many types of steel alloys, including high strength alloys and superalloys.Most molybdenum compounds have low solubility in water, but the molybdate ion MoO2−4 is soluble and forms when molybdenum-containing minerals are in contact with oxygen and water. Industrially, molybdenum compounds (about 14% of world production of the element) are used in high-pressure and high-temperature applications, as pigments, and as catalysts.Molybdenum-containing enzymes are by far the most common catalysts used by some bacteria to break the chemical bond in atmospheric molecular nitrogen, allowing biological nitrogen fixation. At least 50 molybdenum-containing enzymes are now known in bacteria and animals, although only bacterial and cyanobacterial enzymes are involved in nitrogen fixation. These nitrogenases contain molybdenum in a different form from the other molybdenum-containing enzymes, which all contain fully oxidized molybdenum incorporated into a molybdenum cofactor. Owing to the diverse functions of the various molybdenum cofactor enzymes, molybdenum is a required element for life in all higher eukaryote organisms, though it is not required by all bacteria.