Abstract
The molybdenum cofactor isolated from sulfite oxidase (sulfite: ferricytochrome c oxidoreductase, EC 1.8.2.1) and xanthine dehydrogenase (xanthine:NAD+ oxidoreductase, EC 1.2.1.37) in the presence of iodine and KI (form A) has been shown to contain a pterin nucleus with an unidentified substituent in the 6 position [Johnson, J. L., Hainline, B. E. & Rajagopalan, K. V. (1980) J. Biol. Chem. 255, 1783-1786]. A second inactive form of the cofactor was isolated aerobically but in the absence of iodine and KI. The latter cofactor derivative (form B) is highly fluorescent, has a visible absorption band at 395 nm and, like form A, contains a phosphate group. Cleavage of the phosphate ester bond with alkaline phosphatase exposes a glycol function that is sensitive to periodate. Oxidation of form B with alkaline permanganate yields a highly polar compound with properties of a sulfonic acid, suggesting that the active molybdenum cofactor might contain sulfur. The sulfur-containing pterin urothione characterized by Goto et al. [Goto, M., Sakurai, A., Ohta, K. & Yamakami, H. (1969) J. Biochem. 65, 611-620] had been isolated from human urine. The permanganate oxidation product of urothione, characterized by Goto et al. as pterin-6-carboxylic-7-sulfonic acid, is identical to that obtained from form B. Because urothione also contains a periodate-sensitive glycol substituent, a structural relationship is suggested. The finding that urine samples from patients deficient in the molybdenum cofactor are devoid of urothione demonstrates a metabolic link between the two molecules.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Goto M., Sakurai A., Ota K., Yamakami H. Die Struktur des Urothions. J Biochem. 1969 Apr;65(4):611–620. doi: 10.1093/oxfordjournals.jbchem.a129054. [DOI] [PubMed] [Google Scholar]
- Johnson J. L., Hainline B. E., Rajagopalan K. V. Characterization of the molybdenum cofactor of sulfite oxidase, xanthine, oxidase, and nitrate reductase. Identification of a pteridine as a structural component. J Biol Chem. 1980 Mar 10;255(5):1783–1786. [PubMed] [Google Scholar]
- Johnson J. L., Rajagopalan K. V. Purification and properties of sulfite oxidase from human liver. J Clin Invest. 1976 Sep;58(3):543–550. doi: 10.1172/JCI108499. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johnson J. L., Waud W. R., Rajagopalan K. V., Duran M., Beemer F. A., Wadman S. K. Inborn errors of molybdenum metabolism: combined deficiencies of sulfite oxidase and xanthine dehydrogenase in a patient lacking the molybdenum cofactor. Proc Natl Acad Sci U S A. 1980 Jun;77(6):3715–3719. doi: 10.1073/pnas.77.6.3715. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KALCKAR H. M., KJELDGAARD N. O., KLENOW H. 2-Amino-4hydroxy-6-formylpteridine, an inhibitor of purine and pterine oxidases. Biochim Biophys Acta. 1950 Jun;5(3/4):586–594. doi: 10.1016/0006-3002(50)90204-6. [DOI] [PubMed] [Google Scholar]
- Kessler D. L., Rajagopalan K. V. Purification and properties of sulfite oxidase from chicken liver. Presence of molybdenum in sulfite oxidase from diverse sources. J Biol Chem. 1972 Oct 25;247(20):6566–6573. [PubMed] [Google Scholar]
- Meriwether L. S., Marzluff W. F., Hodgson W. G. Molybdenum-thiol complexes as models for molybdenum bound in enzymes. Nature. 1966 Oct 29;212(5061):465–467. doi: 10.1038/212465a0. [DOI] [PubMed] [Google Scholar]
- Sakurai A., Goto M. Die Synthese des Urothions. J Biochem. 1969 May;65(5):755–757. [PubMed] [Google Scholar]