Pulse radiolysis studies of the reaction of nitrogen dioxide with the vitamin B₁₂ complexes Cob(II)alamin and nitrocobalamin
Journal Article
·
· Journal of Inorganic Biochemistry
- Kent State Univ., Kent, OH (United States)
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Auckland Univ. of Technology, Auckland (New Zealand)
Although now recognized to be an important reactive nitrogen species in biological systems that modifies the structures of proteins, DNA and lipids, there few studies on the reactivity of ˙NO2, including the reactions between ˙NO2 and transition metal complexes. We report kinetic studies on the reaction of ˙NO2 with two forms of vitamin B12 – cob(II)alamin and nitrocobalamin. UV-vis spectroscopy and HPLC analysis of the product solution show that ˙NO2 cleanly oxidizes the metal center of cob(II)alamin to form nitrocobalamin, with a second-order rate constant of (3.5 ± 0.3) × 10⁸ M⁻¹ s ⁻¹ (pH 7.0 and 9.0, RT, I = 0.20 M). The stoichiometry of the reaction is 1:1. No reaction is detected by UV-vis spectroscopy and by HPLC analysis of the product solution when nitrocobalamin is exposed to up to 2.0 mol equiv.˙NO2.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1182504
- Alternate ID(s):
- OSTI ID: 1247405
- Report Number(s):
- BNL--107426-2015-JA; KC0304030
- Journal Information:
- Journal of Inorganic Biochemistry, Journal Name: Journal of Inorganic Biochemistry Vol. 142; ISSN 0162-0134
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Studies on the Reduction of Dehydroascorbic Acid by Glutathione in the Presence of Aquahydroxocobinamide: Studies on the Reduction of Dehydroascorbic Acid by Glutathione in the Presence of Aquahydroxocobinamide
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