Molybdenum center of xanthine dehydrogenase

Thesis/Dissertation · Sat Jan 01 04:00:00 EST 1983

OSTI ID:5873200

Wahl, R C

Cyanolysis of native, oxidized xanthine dehydrogenase is known to inactivate the enzyme by removing a unique sulfur as thiocyanate. Chemical, genetic, and spectroscopic evidence indicates that this sulfur is a terminal ligand of Mo and is present in native xanthine dehydrogenase, but not in cyanolyzed xanthine dehydrogenase or native sulfite oxidase. A procedure for rapid, reproducible, and quantitative reconstitution of desulfo Mo hydroxylases with sulfide was developed. The cyanolyzable sulfur of xanthine dehydrogenase was specifically radiolabeled with /sup 35/sulfide using this procedure. Various chemical properties of the cyanolyzable sulfur could be determined with the radiolabelled enzyme. The data support the conclusion that the cyanolyzable sulfur is a terminal sulfur ligand of the Mo atoms, and is not part of an organic moiety. Application of the resulfuration procedure to crude extracts of Drosophila melanogaster ma-1 flies, which are pleiotropically deficient in xanthine dehydrogenase and aldehyde oxidase, led to the emergence of these enzyme activities. Evidence for the identity of in vitro reconstituted xanthine dehydrogenase from ma-1 mutants with wild type enzyme is presented. A system for efficient reconstitution of the apo-subunits of the molybdoenzyme nitrate reductase from the Neurospora crassa mutant nit-1 with molybdenum cofactor from denatured purified molybdoenzymes in the absence of exogenous molybdate was developed.

• Research Organization: Duke Univ., Durham, NC (USA)
• OSTI ID: 5873200
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AROMATICS
ARTHROPODS
AZAARENES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
CHEMICAL PROPERTIES
CHEMISTRY
DAYS LIVING RADIOISOTOPES
DIPTERA
DROSOPHILA
ENZYME ACTIVITY
ENZYMES
EVEN-ODD NUCLEI
FLIES
FRUIT FLIES
FUNGI
HETEROCYCLIC COMPOUNDS
INSECTS
INVERTEBRATES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIGANDS
LIGHT NUCLEI
MOLYBDENUM COMPOUNDS
NEUROSPORA
NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDOREDUCTASES
PLANTS
PURINES
RADIOISOTOPES
REFRACTORY METAL COMPOUNDS
SULFUR 35
SULFUR ISOTOPES
TRACER TECHNIQUES
TRANSITION ELEMENT COMPOUNDS
XANTHINES