Titanium distribution in the lithosphere

Beus, A. A.

doi:10.1016/0009-2541(71)90021-0

“…In contrast, Mo is mostly present as Mo(IV) in jordesite and molybdenite (both MoS 2 [46,48]), minerals that are often associated with wolframite. Reviews on the geology, geochemistry and mineralogy of W can be found in [44,46,47,49,50]. W deposits are usually formed by hydrothermal mineralization and metamorphic processes, typically in subterranean environments, and W can be deposited at the discharge site of thermal waters (see below, [46,51]).…”

Section: Abundance and Chemical Forms Of Tungsten And Molybdenummentioning

confidence: 99%

Tungsten in biological systems

Kletzin¹,

Adams²

1996

FEMS Microbiology Reviews

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Tungsten (atomic number 74) and the chemically analogous and very similar metal molybdenum (atomic number 42) are minor yet equally abundant elements on this planet. The essential role of molybdenum in biology has been known for decades and molybdoenzymes are ubiquitous. Yet, it is only recently that a biological role for tungsten has been established in prokaryotes, although not as yet in eukaryotes. The best characterized organisms with regard to their metabolism of tungsten are certain species of hyperthermophilic archaea (Pyrococcus furiosus and Thermococcus litoralis), methanogens (Methanobacterium thermoautotrophicum and Mb. wolfei), Gram-positive bacteria (Clostridium thermoaceticum, C. formicoaceticum and Eubacterium acidaminophilum), Gram-negative anaerobes (Desulfovibrio gigas and Pelobacter acetylenicus) and Gram-negative aerobes (Methylobacterium sp. RXM). Of these, only the hyperthermophilic archaea appear to be obligately tungsten-dependent. Four different types of tungstoenzyme have been purified: formate dehydrogenase, formyl methanofuran dehydrogenase, acetylene hydratase, and a class of phylogenetically related oxidoreductases that catalyze the reversible oxidation of aldehydes. These are carboxylic reductase, and three ferredoxin-dependent oxidoreductases which oxidize various aldehydes, formaldehyde and glyceraldehyde 3-phosphate. All tungstoenzymes catalyze redox reactions of very low potential (< -420 mV) except one (acetylene hydratase) which catalyzes a hydration reaction. The tungsten in these enzymes is bound by a pterin moiety similar to that found in molybdoenzymes. The first crystal structure of a tungsten-or pterin-containing enzyme, that of aldehyde ferredoxin oxidoreductase from P. furiosus, has revealed a catalytic site with one W atom coordinated to two pterin molecules which are themselves bridged by a magnesium ion. The geochemical, ecological, biochemical and phylogenetic basis for W-vs. Mo-dependent organisms is discussed.

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“…The range of Ti02 content of metamorphic rocks appears to reflect the diversity of parent rocks. The data are much less complete for metamorphic rocks (table 4) than for parent materials (tables 2 and Rock type Amphibolite ---------Gneiss --------------Schi~ ---------------Slate ----------------Greenschist ----------Quartzite ------------Serpentinite ---------Glaucophane schist __ Eclogite ------------- Beus ( 1971) . Do.…”

Section: Metamorphic Rocksmentioning

confidence: 99%

Geology and resources of titanium

Force¹,

Blake²,

Morgan³

et al. 1976

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“…In contrast, Mo is mostly present as Mo(IV) in jordesite and molybdenite (both MoS 2 [46,48]), minerals that are often associated with wolframite. Reviews on the geology, geochemistry and mineralogy of W can be found in [44,46,47,49,50]. W deposits are usually formed by hydrothermal mineralization and metamorphic processes, typically in subterranean environments, and W can be deposited at the discharge site of thermal waters (see below, [46,51]).…”

Section: Abundance and Chemical Forms Of Tungsten And Molybdenummentioning

confidence: 99%

Tungsten in biological systems

Kletzin

¹

,

Adams

²

1996

FEMS Microbiology Reviews

View full text Add to dashboard Cite

Tungsten (atomic number 74) and the chemically analogous and very similar metal molybdenum (atomic number 42) are minor yet equally abundant elements on this planet. The essential role of molybdenum in biology has been known for decades and molybdoenzymes are ubiquitous. Yet, it is only recently that a biological role for tungsten has been established in prokaryotes, although not as yet in eukaryotes. The best characterized organisms with regard to their metabolism of tungsten are certain species of hyperthermophilic archaea (Pyrococcus furiosus and Thermococcus litoralis), methanogens (Methanobacterium thermoautotrophicum and Mb. wolfei), Gram-positive bacteria (Clostridium thermoaceticum, C. formicoaceticum and Eubacterium acidaminophilum), Gram-negative anaerobes (Desulfovibrio gigas and Pelobacter acetylenicus) and Gram-negative aerobes (Methylobacterium sp. RXM). Of these, only the hyperthermophilic archaea appear to be obligately tungsten-dependent. Four different types of tungstoenzyme have been purified: formate dehydrogenase, formyl methanofuran dehydrogenase, acetylene hydratase, and a class of phylogenetically related oxidoreductases that catalyze the reversible oxidation of aldehydes. These are carboxylic reductase, and three ferredoxin-dependent oxidoreductases which oxidize various aldehydes, formaldehyde and glyceraldehyde 3-phosphate. All tungstoenzymes catalyze redox reactions of very low potential (< -420 mV) except one (acetylene hydratase) which catalyzes a hydration reaction. The tungsten in these enzymes is bound by a pterin moiety similar to that found in molybdoenzymes. The first crystal structure of a tungsten-or pterin-containing enzyme, that of aldehyde ferredoxin oxidoreductase from P. furiosus, has revealed a catalytic site with one W atom coordinated to two pterin molecules which are themselves bridged by a magnesium ion. The geochemical, ecological, biochemical and phylogenetic basis for W-vs. Mo-dependent organisms is discussed.

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Titanium distribution in the lithosphere

Cited by 9 publications

References 72 publications

Tungsten in biological systems

Tungsten in biological systems

Geology and resources of titanium

Tungsten in biological systems

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