The relationship of Mo, molybdopterin, and the cyanolyzable sulfur in the Mo cofactor.

Published

Journal Article

Reconstitution of the apoprotein of the molybdoenzyme nitrate reductase in extracts of the Neurospora crassa mutant nit-1 with molybdenum cofactor released by denaturation of purified molybdoenzymes is efficient in the absence of exogenous MoO2-4 under defined conditions. Evidence is presented that this molybdate-independent reconstitution is due to transfer of intact Mo cofactor, a complex of Mo and molybdopterin (MPT), the organic constituent of the cofactor. This complex can be separated from denatured protein by gel filtration, and from excess MoO2-4 by reverse-phase HPLC. Sulfite oxidase, native xanthine dehydrogenase, and cyanolyzed xanthine dehydrogenase are equipotent Mo cofactor donors. Other well-studied inactive forms of xanthine dehydrogenase are also shown to be good cofactor sources. Using xanthine dehydrogenase specifically radiolabeled in the cyanolyzable sulfur, it is shown that this terminal ligand of Mo is rapidly removed from Mo cofactor under the conditions used for reconstitution.

Full Text

Duke Authors

Cited Authors

  • Wahl, RC; Hageman, RV; Rajagopalan, KV

Published Date

  • April 1984

Published In

Volume / Issue

  • 230 / 1

Start / End Page

  • 264 - 273

PubMed ID

  • 6231887

Pubmed Central ID

  • 6231887

International Standard Serial Number (ISSN)

  • 0003-9861

Digital Object Identifier (DOI)

  • 10.1016/0003-9861(84)90107-3

Language

  • eng

Conference Location

  • United States