Structure of the active site of sulfite oxidase. X-ray absorption spectroscopy of the Mo(IV), Mo(V), and Mo(VI) oxidation states

Journal Article · Tue Jun 13 04:00:00 EDT 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00438a026· OSTI ID:5431337

George, G N; Kipke, C A; Prince, R C; Sunde, R A; Enemark, J H; Cramer, S P ^[1]

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1. Exxon Research and Engineering Company, Annandale, NJ (USA)

The active site of sulfite oxidase has been investigated by X-ray absorption spectroscopy at the molybdenum K-edge at 4 K. The authors have investigated all three accessible molybdenum oxidation states, Mo(IV), Mo(V), and Mo(VI), allowing comparison with the Mo(V) electron paramagnetic resonance data for the first time. Quantitative analysis of the extended X-ray absorption fine structure indicates that the Mo(VI) oxidation state possesses two terminal oxo (Mo{double bond}O) and approximately three thiolate-like (Mo{emdash}S-) ligands and is unaffected by changes in pH and chloride concentration. The Mo(IV) and Mo(V) oxidation states, however, each have a single oxo ligand plus one Mo{emdash}O- (or Mo-N<) bond, most probably Mo{emdash}OH, and two to three thiolate-like ligands. Both reduced forms appear to gain a single chloride ligand under conditions of low pH and high chloride concentration.

• OSTI ID: 5431337
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 28:12; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550602* -- Medicine-- External Radiation in Diagnostics-- (1980-)
62 RADIOLOGY AND NUCLEAR MEDICINE
ABSORPTION SPECTROSCOPY
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMICAL STATE
ENZYMES
IONS
MOLECULAR STRUCTURE
MOLYBDENUM COMPOUNDS
OXIDATION
OXIDOREDUCTASES
PH VALUE
REFRACTORY METAL COMPOUNDS
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
X-RAY SPECTROSCOPY