Molybdenum Nutriture in Humans

Molybdenum is a trace element that functions as a cofactor for at least 4 enzymes: sulfite oxidase, xanthine oxidase, aldehyde oxidase, and mitochondrial amidoxime reducing component. In each case, molybdenum is bound to a complex, multiring organic component called molybdopterin, forming the entity molybdenum cofactor. The best sources of dietary molybdenum are legumes, grains, and nuts. Bioavailability of molybdenum is fairly high but depends on form, with molybdenum preparations having greater bioavailability than food-bound molybdenum. Molybdenum deficiency and toxicity are rare, possibly because of the body’s ability to adapt to a wide range of molybdenum intake levels. At low intakes of molybdenum, the fractional transfer of molybdenum from plasma to urine is lower and a greater fraction is deposited into tissues, and at high intakes of molybdenum, the opposite occurs. Molybdenum has proven to be an interesting trace mineral that is essential for life.

Download Full-text

Combined deficiency of sulfite oxidase and xanthine oxidase as a result of defective synthesis of molybdenum-cofactor: 77

Pediatric Research ◽

10.1203/00006450-198002000-00104 ◽

1980 ◽

Vol 14 (2) ◽

pp. 177-177 ◽

Cited By ~ 1

Author(s):

M Duran ◽

F A Beemer ◽

S K Wadman ◽

J L Johnson ◽

W R Waud ◽

...

Keyword(s):

Xanthine Oxidase ◽

Sulfite Oxidase ◽

Molybdenum Cofactor ◽

Combined Deficiency

Download Full-text

The structure of the molybdenum cofactor. Characterization of di-(carboxamidomethyl)molybdopterin from sulfite oxidase and xanthine oxidase.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)49263-0 ◽

1987 ◽

Vol 262 (34) ◽

pp. 16357-16363 ◽

Cited By ~ 13

Author(s):

SP Kramer ◽

JL Johnson ◽

AA Ribeiro ◽

DS Millington ◽

KV Rajagopalan

Keyword(s):

Xanthine Oxidase ◽

Sulfite Oxidase ◽

Molybdenum Cofactor

Download Full-text

Characterization of the molybdenum cofactor of sulfite oxidase, xanthine, oxidase, and nitrate reductase. Identification of a pteridine as a structural component.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)85945-8 ◽

1980 ◽

Vol 255 (5) ◽

pp. 1783-1786

Author(s):

J.L. Johnson ◽

B.E. Hainline ◽

K.V. Rajagopalan

Keyword(s):

Nitrate Reductase ◽

Xanthine Oxidase ◽

Structural Component ◽

Sulfite Oxidase ◽

Molybdenum Cofactor

Download Full-text

Identification and Biochemical Characterization ofArabidopsis thalianaSulfite Oxidase

Journal of Biological Chemistry ◽

10.1074/jbc.m108078200 ◽

2001 ◽

Vol 276 (50) ◽

pp. 46989-46994 ◽

Cited By ~ 119

Author(s):

Thomas Eilers ◽

Günter Schwarz ◽

Henner Brinkmann ◽

Christina Witt ◽

Tim Richter ◽

...

Keyword(s):

Biochemical Characterization ◽

Sulfite Oxidase ◽

Molybdenum Cofactor ◽

Active Centers ◽

Oxidase Gene ◽

Cell Extracts ◽

Redox Active ◽

Wide Range ◽

Heme Domain ◽

Molybdenum Enzyme

In mammals and birds, sulfite oxidase (SO) is a homodimeric molybdenum enzyme consisting of an N-terminal heme domain and a C-terminal molybdenum domain (EC1.8.3.1). In plants, the existence of SO has not yet been demonstrated, while sulfite reductase as part of sulfur assimilation is well characterized. Here we report the cloning of a plant sulfite oxidase gene fromArabidopsis thalianaand the biochemical characterization of the encoded protein (At-SO). At-SO is a molybdenum enzyme with molybdopterin as an organic component of the molybdenum cofactor. In contrast to homologous animal enzymes, At-SO lacks the heme domain, which is evident both from the amino acid sequence and from its enzymological and spectral properties. Thus, among eukaryotes, At-SO is the only molybdenum enzyme yet described possessing no redox-active centers other than the molybdenum. UV-visible and EPR spectra as well as apparentKmvalues are presented and compared with the hepatic enzyme. Subcellular analysis of crude cell extracts showed that SO was mostly found in the peroxisomal fraction. In molybdenum cofactor mutants, the activity of SO was strongly reduced. Using antibodies directed against At-SO, we show that a cross-reacting protein of similar size occurs in a wide range of plant species, including both herbacious and woody plants.

Download Full-text

Chain-breaking/Preventive Antioxidant, Urate-lowering, and Anti-inflammatory Effects of Pure Curcumin

Current Nutrition & Food Science ◽

10.2174/1573401316999200421095134 ◽

2020 ◽

Vol 17 (1) ◽

pp. 66-74

Author(s):

Seghira Bisset ◽

Widad Sobhi ◽

Chawki Bensouici ◽

Abdelhalim Khenchouche

Keyword(s):

Uric Acid ◽

Xanthine Oxidase ◽

Acid Production ◽

Biological Activities ◽

Antioxidant Effect ◽

Metal Chelating ◽

Wide Range ◽

Chain Breaking ◽

Pharmaceutical Industries ◽

Anti Inflammatory

Background: Several researches have shown that therapeutic compounds or phytochemicals from natural sources are important in the food as it is valuable in pharmaceutical industries due to their fewer side effects and potent against various diseases. Curcumin, a major polyphenol derived from turmeric spice, which used in many foods, has a wide range of biological activities, with quite a safety. Objective: The goal of this study was to investigate the antioxidant, urate-lowering, and antiinflammatory effects of pure curcumin. Methods: The antioxidant activity was evaluated for chain-breaking antioxidant effect (radicalscavenging and reducing abilities assays) and for preventive antioxidant effect with metal chelating assay, the urate-lowering was assayed on aspectrophotometer by measuring the inhibition of uric acid production by xanthine oxidase (XO) enzyme, and the anti-inflammatory effect was estimated using in vitro albumin denaturation inhibition. Results: Curcumin showed a significant and good chain-breaking antioxidant effect, both in free radical- scavenging assays (Galvinoxyl radical, ABTS, and hydroxyl radical), and in reducing abilities methods (reducing power, Cupric ion reducing antioxidant capacity and O-phenanthroline assays). In preventive antioxidant effect, assessed with the metal chelating assay, curcumin showed significant effect but with high concentration compared with standard. In the xanthine/xanthine oxidase system, curcumin significantly inhibited uric acid production (IC50=0.71 ± 0.06 mg/mL). Regarding antiinflammatory activity, curcumin showed significant inhibition of albumin denaturation with an IC50 value of 1181.69 ± 1.11μg/mL. Conclusion: These results indicated that curcumin showed promising antioxidant, anti-gout and antiinflammatory properties and might be used as potential, natural drugs against oxidative and inflammation- related diseases.

Download Full-text

Studies by electron paramagnetic resonance spectroscopy of the environment of the metal in the molybdenum cofactor from xanthine oxidase

Flavins and Flavoproteins ◽

10.1515/9783111521350-057 ◽

1984 ◽

pp. 323-324

Keyword(s):

Electron Paramagnetic Resonance ◽

Xanthine Oxidase ◽

Electron Paramagnetic Resonance Spectroscopy ◽

Molybdenum Cofactor ◽

Resonance Spectroscopy ◽

Paramagnetic Resonance ◽

Electron Paramagnetic

Download Full-text

Identification of persulfide-binding and disulfide-forming cysteine residues in the NifS-like domain of the molybdenum cofactor sulfurase ABA3 by cysteine-scanning mutagenesis

Biochemical Journal ◽

10.1042/bj20111170 ◽

2012 ◽

Vol 441 (3) ◽

pp. 823-839 ◽

Cited By ~ 16

Author(s):

Markus Lehrke ◽

Steffen Rump ◽

Torsten Heidenreich ◽

Josef Wissing ◽

Ralf R. Mendel ◽

...

Keyword(s):

Structural Model ◽

Bond Distance ◽

Aldehyde Oxidase ◽

Disulfide Bridge ◽

Cysteine Residue ◽

Molybdenum Cofactor ◽

Cysteine Residues ◽

Xanthine Oxidoreductase ◽

Cysteine Scanning Mutagenesis ◽

Molybdenum Cofactor Sulfurase

The Moco (molybdenum cofactor) sulfurase ABA3 from Arabidopsis thaliana catalyses the sulfuration of the Moco of aldehyde oxidase and xanthine oxidoreductase, which represents the final activation step of these enzymes. ABA3 consists of an N-terminal NifS-like domain that exhibits L-cysteine desulfurase activity and a C-terminal domain that binds sulfurated Moco. The strictly conserved Cys430 in the NifS-like domain binds a persulfide intermediate, which is abstracted from the substrate L-cysteine and finally needs to be transferred to the Moco of aldehyde oxidase and xanthine oxidoreductase. In addition to Cys430, another eight cysteine residues are located in the NifS-like domain, with two of them being highly conserved among Moco sulfurase proteins and, at the same time, being in close proximity to Cys430. By determination of the number of surface-exposed cysteine residues and the number of persulfide-binding cysteine residues in combination with the sequential substitution of each of the nine cysteine residues, a second persulfide-binding cysteine residue, Cys206, was identified. Furthermore, the active-site Cys430 was found to be located on top of a loop structure, formed by the two flanking residues Cys428 and Cys435, which are likely to form an intramolecular disulfide bridge. These findings are confirmed by a structural model of the NifS-like domain, which indicates that Cys428 and Cys435 are within disulfide bond distance and that a persulfide transfer from Cys430 to Cys206 is indeed possible.

Download Full-text

Oxidation of Selected Pteridine Derivatives by Mammalian Liver Xanthine Oxidase and Aldehyde Oxidase

Journal of Pharmaceutical Sciences ◽

10.1002/jps.2600650806 ◽

1976 ◽

Vol 65 (8) ◽

pp. 1150-1154 ◽

Cited By ~ 21

Author(s):

C.N. Hodnett ◽

J.J. McCormack ◽

J.A. Sabean

Keyword(s):

Xanthine Oxidase ◽

Aldehyde Oxidase ◽

Mammalian Liver ◽

Pteridine Derivatives

Download Full-text

Phenylacetaldehyde Oxidation by Freshly Prepared and Cryopreserved Guinea Pig Liver Slices: The Role of Aldehyde Oxidase

International Journal of Toxicology ◽

10.1080/10915810590936373 ◽

2005 ◽

Vol 24 (2) ◽

pp. 103-109 ◽

Cited By ~ 5

Author(s):

Georgios I. Panoutsopoulos

Keyword(s):

Guinea Pig ◽

Xanthine Oxidase ◽

Aldehyde Dehydrogenase ◽

Phenylacetic Acid ◽

Aldehyde Oxidase ◽

Acid Formation ◽

Pig Liver ◽

Liver Slices ◽

Inhibited Acid ◽

Guinea Pig Liver

Phenylacetaldehyde is formed when the xenobiotic and biogenic amine 2-phenylethylamine is inactivated by a monoamine oxidase–catalyzed oxidative deamination. Exogenous phenylacetaldehyde is found in certain foodstuffs such as honey, cheese, tomatoes, and wines. 2-Phenylethylamine can trigger migraine attacks in susceptible individuals and can become fairly toxic at high intakes from foods. It may also function as a potentiator that enhances the toxicity of histamine and tyramine. The present investigation examines the metabolism of phenylacetaldehyde to phenylacetic acid in freshly prepared and in cryopreserved guinea pig liver slices. In addition, it compares the relative contribution of aldehyde oxidase, xanthine oxidase, and aldehyde dehydrogenase in the oxidation of phenylacetaldehyde using specific inhibitors for each oxidizing enzyme. The inhibitors used were isovanillin for aldehyde oxidase, allopurinol for xanthine oxidase, and disulfiram for aldehyde dehydrogenase. In freshly prepared liver slices, phenylacetaldehyde was converted mainly to phenylacetic acid, with traces of 2-phenylethanol being present. Disulfiram inhibited phenylacetic acid formation by 80% to 85%, whereas isovanillin inhibited acid formation to a lesser extent (50% to 55%) and allopurinol had little or no effect. In cryopreserved liver slices, phenylacetic acid was also the main metabolite, whereas the 2-phenylethanol production was more pronounced than that in freshly prepared liver slices. Isovanillin inhibited phenylacetic acid formation by 85%, whereas disulfiram inhibited acid formation to a lesser extent (55% to 60%) and allopurinol had no effect. The results in this study have shown that, in freshly prepared and cryopreserved liver slices, phenylacetaldehyde is converted to phenylacetic acid by both aldehyde dehydrogenase and aldehyde oxidase, with no contribution from xanthine oxidase. Therefore, aldehyde dehydrogenase is not the only enzyme responsible in the metabolism of phenylacetaldehyde, but aldehyde oxidase may also be important and thus its role should not be ignored.

Download Full-text