Nitroxylcob(III)alamin: Synthesis and X‐ray Structural Characterization

Hannibal, Luciana; Smith, Clyde A.; Jacobsen, Donald W.; Brasch, Nicola E.

doi:10.1002/anie.200701131

Cited by 50 publications

(54 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Based on our data, K 1 = (1.29 ± 0.01) × 10 3 /(1.42 ± 0.03) × 10 −2 = (9.1 ± 0.3) × 10 4 M −1 at 25 °C, which is close to the different values reported in the literature for the complex-formation constant of CblNO 2 , viz. 8.5 × 10 4 M −1 according to Walker et al [14] and 2.2 × 10 5 M −1 as reported by Marques et al [11].…”

supporting

confidence: 68%

“…Up to now it was shown that there is no direct interaction between NO and aquacobalamin at physiological pH [10]. However, the reduced form of aquacobalamin binds NO rapidly and reversibly to form nitroxylcobalamin, CblNO: [7] Nitroxylcobalamin is oxygen sensitive; in the presence of air it rapidly oxidizes to nitrocobalamin CblNO 2 [11]. Nitrocobalamin is one of the naturally occurring forms of (1) Cbl(II) + NO ⇄ Cbl(III)NO − cobalamin and was isolated from biological samples, thus it is stable in biological systems [12,13].…”

Section: Electronic Supplementary Materialsmentioning

confidence: 98%

See 1 more Smart Citation

Mechanistic information on the nitrite-controlled reduction of aquacob(III)alamin by ascorbate at physiological pH

et al. 2015

View full text Add to dashboard Cite

The interaction with nitric oxide (NO) is an important aspect of the biological activity of vitamin B12 (Cbl). Whereas the formation of nitroxylcobalamin (CblNO) via the binding of NO to reduced CblCo(II) has been studied in detail before, the possible intracellular formation of CblNO via reduction of nitrocobalamin (CblNO2) is still questionable. To study this further, spectroscopic and kinetic studies on the reaction of CblNO2 with the intracellular antioxidant ascorbic acid (Asc) were performed in aqueous solution at the physiological pH of 7.2. It was found that the redox pathway of this reaction requires anaerobic conditions as a result of the rapid re-oxidation of reduced CblCo(II). In the studied system, both CblOH2 and CblNO2 are reduced to CblCo(II) by ascorbate at pH 7.2, the CblOH2 complex being two orders of magnitude more reactive than CblNO2. Clear evidence for redox cycling between CblOH2/CblNO2 and CblCo(II) under aerobic conditions was observed as an induction period during which all oxygen was used prior to the formation of CblCo(II) in the presence of an excess of ascorbate. No evidence for the intermediate formation of CblNO or NO radicals during the reduction of CblNO2 could be found. Nitrocob(III)alamin can be reduced by ascorbic acid under physiological conditions. The products of the reaction are cob(II)alamin and nitrite ion. This reaction is ca. 200 times slower than the one involving aquacob(III)alamin.

show abstract

supporting

confidence: 68%

Section: Electronic Supplementary Materialsmentioning

confidence: 98%

Mechanistic information on the nitrite-controlled reduction of aquacob(III)alamin by ascorbate at physiological pH

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Very recently, Brasch et al have shown that extension of this correlation to a larger number of cobalamins having distances with e.s.d. 's up to 0.01 Å, gave an R 2 value of 0.84 [39,40,43]. However, when the correlation is limited to Co\NB3 distances with e.s.d.…”

Section: Co-c (å)mentioning

confidence: 90%

“…2. The distance increases from 1.925(2) Å, when X is the very weak σ-donor H 2 O, to 2.351(2) Å, when X is the strong σ-donor NO: the latter is a significantly stronger trans influencing ligand than even an alkyl group [39,40]. In contrast to NOCbl, nitrosylcobaloxime is pentacoordinate and represents, to our knowledge, the only example so far known of a crystallographically characterized pentacoordinate Co(III) dioximate [41].…”

Section: Trans Influencementioning

confidence: 96%

Trans and cis influences and effects in cobalamins and in their simple models

March

Demitri

Geremia

et al. 2012

Journal of Inorganic Biochemistry

View full text Add to dashboard Cite

“…Other analogs with Schiff bases, dithiocarbamates, dimethylglyoximates, and other chelating coligands have been prepared (150). Most significant was the isolation in 2007 of nitroxylcobal(III)amin (NOCbl, containing a corrin ring), obtained by reaction of hydroxycobalamineÁHCl with a NONOate (151). The Co-N α axial bond length to the DMB ligand of NOCbl is greater by 0.13 Å than the distance in the related NO 2 Cbl structure, reflecting the trans-labilizing effect of NO À .…”

Section: No 2 -Complexesmentioning

confidence: 98%