Kinetic Studies on the Reaction between Cob(I)alamin and Peroxynitrite: Rapid Oxidation of Cob(I)alamin to Cob(II)alamin by Peroxynitrous Acid

✍ Scribed by Dr. Riya Mukherjee; Dr. Nicola E. Brasch

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 260 KB
• Volume: 17
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.201102267

✦ Synopsis

There is currently much interest in the biochemical reactivity of peroxynitrite/peroxynitrous acid (ONOO À / ONOOH; pK a(ONOOH) = 6.8), [1] a strong oxidizing, hydroxylating and/or nitrating agent formed by the diffusion controlled reaction of nitric oxide with superoxide. [1] Elevated peroxynitrite levels are associated with chronic inflammatory disorders including neurological and vascular diseases, and circulatory shock. [1, 2] ONOO(H) or its decomposition products react rapidly in vivo with amino acids, bases of nucleotides, lipids, circulatory CO 2 , metalloproteins, thiols and antioxidants. [1, 2] Nitration of tyrosine protein residues is widely used as a biomarker for elevated peroxynitrite levels. [1, 2b] Cobalamins (Cbls, vitamin B 12 derivatives, Scheme 1) are essential Co III macrocyclic cofactors for two mammalian enzymes: adenosylcobalamin-dependent l-methylmalonyl-[a] Dr.