Overestimation of cyanocobalamin due to coelution of sulfitocobalamin on SP-Sephadex C-25

Begley, James A.; Hall, Charles A.

doi:10.1016/s0021-9673(01)96334-4

Cited by 13 publications

(6 citation statements)

References 10 publications

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“…For example, the percentage of reduced thiol which undergoes B 12 -catalyzed aerial oxidation to its inactive disulfide form (disulfides do not react with aquacobalamin 44 ) during the synthesis of thiolatocobalamins from aquacobalamin is considerably less if the synthesis is carried out at high concentrations, and can remove the need for a large excess of the reduced thiol and/or anaerobic conditions. Sulfitocobalamin (SO 3 Cbl − ) is a biologically important B 12 metabolite, [11][12][13][14][15][16][17] and there are several reports concerning the synthesis and isolation of this derivative. 15,37,93 These methods require a large excess of sulfite to obtain complete formation of SO 3 Cbl − , requiring subsequent de-salting of the product using column chromatography.…”

Section: Synthesis and Characterization Of Sulfitocobalamin And Nitromentioning

confidence: 99%

“…Sulfitocobalamin (SO 3 Cbl − ) is a biologically important B 12 metabolite, [11][12][13][14][15][16][17] and there are several reports concerning the synthesis and isolation of this derivative. 15,37,93 These methods require a large excess of sulfite to obtain complete formation of SO 3 Cbl − , requiring subsequent de-salting of the product using column chromatography. B 12 -catalyzed oxidation of sulfite to sulfate can also result in the product being contaminated by the byproduct sulfatocobalamin.…”

Section: Synthesis and Characterization Of Sulfitocobalamin And Nitromentioning

confidence: 99%

“…Adenosylcobalamin, methylcobalamin and aquacobalamin (H 2 OCbl + ↔ HOCbl + H + ; pK a = 7.8) 6 are the major cobalamin metabolites isolated from biological samples. [7][8][9][10] Sulfitocobalamin (SO 3 Cbl − ) is also isolable from mammalian cells and foods, [9][10][11][12][13][14][15][16][17][18][19] and there are also reports of the isolation of nitrocobalamin (NO 2 Cbl) from biological sources. 11,20 Whether or not cyanocobalamin is truly 'naturally occurring' is controversial; some studies report small amounts of this derivative, especially in smokers.…”

Section: Introductionmentioning

confidence: 99%

“…Although both are isolable from biological samples, [11][12][13][14][15][16][17]20 and are well studied and structurally characterized, 23,29,38,43,[59][60][61][62][63][64][65][66][67][68][69] neither are commercially available. NO 2 Cbl is also of interest, since if nitrosylcobalamin (NOCbl) is formed in biological systems to any appreciable extent, NO 2 Cbl rather than NOCbl will be isolated after typical (aerobic) isolation and purification procedures.…”

Section: Introductionmentioning

confidence: 99%

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A simple, convenient method to synthesize cobalamins: synthesis of homocysteinylcobalamin, N-acetylcysteinylcobalamin, 2-N-acetylamino-2-carbomethoxyethanethiolatocobalamin, sulfitocobalamin and nitrocobalamin

et al. 2006

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Glutathionylcobalamin, nitrocobalamin and sulfitocobalamin are important cobalamin metabolites isolable from human tissues. Herein we demonstrate that a procedure used to synthesize and isolate γ-glutamylcysteinylcobalamin and glutathionylcobalamin in aqueous solution in high yield and purity can be used to synthesize other novel, biologically relevant thiolatocobalamins, including D,Lhomocysteinylcobalamin, N-acetyl-L-cysteinylcobalamin (Na + salt) and 2-N-acetylamino-2-carbomethoxy-L-ethanethiolatocobalamin, as well as other non-alkylcobalamins, such as sulfitocobalamin (Na + salt) and nitrocobalamin. This uncomplicated, general procedure will assist researchers in identifying unknown cobalamin metabolites isolated from biological samples, and researchers interested in studying the uptake and intracellular cobalamin processing mechanisms utilizing non-alkylcobalamin derivatives that are not yet commercially available. The X-ray structure and XAS spectrum of N-acetyl-L-cysteinylcobalamin are also presented.

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Section: Synthesis and Characterization Of Sulfitocobalamin And Nitromentioning

confidence: 99%

Section: Synthesis and Characterization Of Sulfitocobalamin And Nitromentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A simple, convenient method to synthesize cobalamins: synthesis of homocysteinylcobalamin, N-acetylcysteinylcobalamin, 2-N-acetylamino-2-carbomethoxyethanethiolatocobalamin, sulfitocobalamin and nitrocobalamin

et al. 2006

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“…The major Cbls extracted and identified in these early studies included methylcobalamin (MeCbl), adenosylcobalamin (Ado-Cbl) and aqua(hydroxo)cobalamin (H 2 OCbl + /HOCbl) [reviewed by Gimsing and Nexo (18)]. Other studies have reported that sulfitocobalamin (SO 3 Cbl), nitrocobalamin (NO 2 Cbl), and the extremely air-sensitive derivative nitroxylcobalamin (NOCbl) are present in biological samples (19)(20)(21).…”

Section: Introductionmentioning

confidence: 99%

Accurate assessment and identification of naturally occurring cellular cobalamins

Hannibal¹,

Axhemi²,

Глущенко³

et al. 2008

Clinical Chemistry and Laboratory Medicine

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The metabolism of cobalamin bound to transcobalamin II and to glycoproteins that bind Cbl in HepG2 cells (human hepatoma)

Hall

Green-Colligan

Begley

1985

Journal Cellular Physiology

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The binding, internalization, processing and release of labeled cyanocobalamin (CN[57Co]Cbl) bound to human transcobalamin II (TC II) were studied in HepG2 cells, a line of hepatocytes derived from a human hepatoma. The cells bound the TC II-Cbl by specific, high affinity receptors. Within the cell, the CN-Cbl was promptly freed from TC II and the CN-Cbl converted to more active forms including adenosyl Cbl (AdoCbl) and methyl Cbl (MeCbl). Whereas free labeled Cbl was still present at 72 hours after entry, the cells also bound Cbl to an intracellular binder (ICB) presumed to represent the holo enzymes dependent on Cbl. At levels of TC II that saturated the receptors for TC II-Cbl, much of the Cbl entering the cells remained free and was converted to AdoCbl. Under these circumstances the cells released free Cbl, mostly AdoCbl. Human R type binders of Cbl, which are glycoproteins and some having a terminal galactose, were bound by the HepG2 cells. The binding was characteristic of the receptor system responsive to a terminal galactose, or asialoglycoproteins, but was inconsistent and of low affinity. Cbl bound to R binder was internalized and converted to coenzyme forms of Cbl, but the process was much less effective than when the Cbl entered via the TC II receptor system. It was concluded that the receptors for R-Cbl were unlikely to contribute to the physiologic transport of Cbl in man, but may function in some yet unknown way.

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Overestimation of cyanocobalamin due to coelution of sulfitocobalamin on SP-Sephadex C-25

Cited by 13 publications

References 10 publications

A simple, convenient method to synthesize cobalamins: synthesis of homocysteinylcobalamin, N-acetylcysteinylcobalamin, 2-N-acetylamino-2-carbomethoxyethanethiolatocobalamin, sulfitocobalamin and nitrocobalamin

A simple, convenient method to synthesize cobalamins: synthesis of homocysteinylcobalamin, N-acetylcysteinylcobalamin, 2-N-acetylamino-2-carbomethoxyethanethiolatocobalamin, sulfitocobalamin and nitrocobalamin

Accurate assessment and identification of naturally occurring cellular cobalamins

The metabolism of cobalamin bound to transcobalamin II and to glycoproteins that bind Cbl in HepG2 cells (human hepatoma)

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