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

Published

Journal Article

A di-(carboxamidomethyl) derivative of molybdopterin, the organic component of the molybdenum cofactor, has been prepared under conditions favoring retention of all of the structural features of the molecule. The specific radioactivity of [1-14C]iodoacetamide incorporated relative to the amount of phosphate indicated two alkylation sites per pterin. Energy-dispersive x-ray analysis of the derivative showed the presence of 2 sulfurs in the derivative. An exact mass corresponding to the molecular formula C14H18N7O5S2 was obtained for the MH+ ion of the alkylated, dephosphorylated compound by fast atom bombardment mass spectroscopy. 1H NMR spectra of the phosphorylated and dephosphorylated forms of alkylated molybdopterin, in conjunction with the other data, have provided strong corroboration of the validity of the proposed structure of molybdopterin (Johnson, J. L., and Rajagopalan, K. V. (1982) Proc. Natl. Acad. Sci. U. S. A. 79, 6856-6860) as a 6-alkylpterin with a 4-carbon side chain containing an enedithiol on C-1' and C-2', a secondary alcohol on C-3', and a phosphorylated primary alcohol on C-4'. As isolated, the di-(carboxamido-methyl)molybdopterin was found to be a 5,6,7,8-tetrahydropterin.

Full Text

Duke Authors

Cited Authors

  • Kramer, SP; Johnson, JL; Ribeiro, AA; Millington, DS; Rajagopalan, KV

Published Date

  • December 5, 1987

Published In

Volume / Issue

  • 262 / 34

Start / End Page

  • 16357 - 16363

PubMed ID

  • 3680253

Pubmed Central ID

  • 3680253

International Standard Serial Number (ISSN)

  • 0021-9258

Language

  • eng

Conference Location

  • United States