HYDROLYSIS PRODUCTS OF PSEUDOVITAMIN B<sub>12</sub>

Dion, Henry W.; Calkins, D. G.; Pfiffner, J. J.

doi:10.1021/ja01124a535

Cited by 50 publications

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“…Nature provides us with a spectrum of −complete× corrinoids that differ from vitamin B 12 (6) and other cobalamins by the constitution of their nucleotide base [11] [24] [26].…”

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confidence: 99%

Pseudocoenzyme B12 and Adenosyl-Factor A: Electrochemical Synthesis and Spectroscopic Analysis of Two Natural B12 Coenzymes with Predominantly ‘Base-off' Constitution

Fieber

Hoffmann

Schmidt

et al. 2002

HCA

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Pseudocoenzyme B 12 ( Cob-(5'-deoxy-5'-adenosyl)-(adenin-7-yl)cobamide; 1) and adenosyl-factor A ( Cob-(5'-deoxy-5'-adenosyl)-(2-methyladenin-7-yl)cobamide; 3) are two natural analogues of coenzyme B 12 ( adenosylcobalamin-Cob-(5'-deoxy-5'-adenosyl)-(5,6-dimethyl-1H-benzimidazolyl)cobamide; 2), where the Co-coordinating 5,6-dimethyl-1H-benzimidazole nucleotide base of 2 is replaced by the purine bases adenine and 2-methyladenine. In contrast to 2, which exists solely in the −base-on× form, UV/VIS spectroscopy qualitatively indicates −base-off× constitution for 1 and 3 in aqueous solution. (cf. the established −base-off× form as unexpected binding mode of B 12 cofactors in several B 12 -dependent enzymes, such as in methionine synthase from Escherichia coli and in glutamate mutase from Clostridium cochlearium). In the present work, pseudocoenzyme B 12 (1) was synthesized in 85% yield by alkylation with 5'-O-tosyladenosine of (adenin-7-yl)cob(I)amide, which was produced electrochemically from pseudovitamin B 12 (Cob-cyano-(adenin-7-yl)cobamide). Likewise, adenosyl-factor A (3) was prepared in ca. 70% yield from factor A ( Cob-cyano-(2-methyladenin-7-yl)cobamide; 5). All the spectroscopic properties of 1 and 3 in aqueous solution indicated that these two Cob-(5'-deoxy-5'-adenosyl)-(adenin-7-yl)cobamides exist predominantly in a −base-off× constitution, with minor but significant contributions of the −base-on× form. From the UV/VIS spectra, the temperature-dependent equilibrium constants of the −base-off×/−base-on× reconstitution reaction were determined as K on (1) 0.30 and K on (3) 0.48 at 258, corresponding to a contribution of the −base-on× forms of 23% for 1 and of 32% for 3.

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“…Nature provides us with a spectrum of −complete× corrinoids that differ from vitamin B 12 (6) and other cobalamins by the constitution of their nucleotide base [11] [24] [26].…”

mentioning

confidence: 99%

Pseudocoenzyme B12 and Adenosyl-Factor A: Electrochemical Synthesis and Spectroscopic Analysis of Two Natural B12 Coenzymes with Predominantly ‘Base-off' Constitution

Fieber

Hoffmann

Schmidt

et al. 2002

HCA

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“…Three years after the discovery of vitamin B 12 (62,64), pseudovitamin B 12 was isolated from an incompletely identified microorganism that was obtained from rumen contents (20). In 1958 the coenzyme form of pseudovitamin B 12 (i.e., pseudocoenzyme B 12 ) was discovered and identified by UV and visible (UV-Vis) spectroscopy to be the native cofactor of Clostridium tetanomorphum (2).…”

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Native Corrinoids fromClostridium cochleariumAre Adeninylcobamides: Spectroscopic Analysis and Identification of Pseudovitamin B₁₂and Factor A

et al. 2000

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The corrinoids from the obligate anaerobe Clostridium cochlearium were extracted as a mixture of Co ␤ -cyano derivatives. From 50 g of frozen cells, approximately 2 mg (1.5 mol) of B 12 derivatives was obtained as a crystalline sample. Analysis of the corrinoid sample of C. cochlearium by a combination of high-pressure liquid chromatography and UV-Vis absorbance spectroscopy revealed the presence of three cyano corrinoids in a ratio of about 3:1:1. The spectroscopic data acquired for the sample indicated the main components to be pseudovitamin B 12 (Co ␤ -cyano-7؆-adeninylcobamide) (60%) and factor A (Co ␤ -cyano-7؆-[2-methyl]adeninylcobamide) (20%). Authentic pseudovitamin B 12 was prepared by guided biosynthesis from cobinamide and adenine. Both pseudovitamin B 12 and its homologue, factor A, were subjected to complete spectroscopic analysis by UV-Vis, circular dichroism, mass spectrometry, and by one-and two-dimensional 1 H, 13 C-, and 15 N nuclear magnetic resonance (NMR) spectroscopy. The third component was indicated by the mass spectra to be an isomer of factor A and is likely (according to NMR) to be 7؆-[N 6 -methyl]-adeninylcobamide, a previously unknown corrinoid. C. cochlearium thus biosynthesizes as its native "complete" B 12 cofactors the 7؆-adeninylcobamides and two homologous corrinoids, in which the nucleotide base is a methylated adenine.

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“…1, the pentose linked to the S,6-dimethylbenzimidazole moiety in vitamin B~ is ribose (I). The nucleoside adenosine, which also contains ribose (II) is present not only in pseudovitamin B12 (10) and in ribose nucleic acids but also in ADP and ATP and in several coenzymes. The present studies on inhibition of influenza virus multiplication were carried out with alkyl-, chloro-, or alkyl-chlorobenzimidazoles; the benzimidazole glycosides were derived from ribose and other pentoses, or certain hexoses.…”

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Inhibition of Influenza Virus Multiplication by N-Glycosides of Benzimidazoles

Tamm¹,

Folkers²,

Shunk³

et al. 1954

Journal of Experimental Medicine

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Chloro derivatives of benzimidazole were found to be 2 to 3 times more active than corresponding methyl derivatives in causing inhibition of Lee virus multiplication in chorioallantoic membrane cultures in vitro. The most active benzimidazole derivative thus far tested is 5,6-dichloro-1-ß-D-ribofuranosylbenzimidazole (DRB); it caused 75 per cent inhibition of Lee virus multiplication in membrane cultures at a concentration of 0.38 x 10–4 M. On the other hand, 5,6-dimethyl-1-alpha;-D-ribofuranosylbenzimidazole, the moiety present in vitamin B12, failed to inhibit Lee virus multiplication at a concentration of 35 x 10–4 M. Other N-glycosides of 5,6-dichlorobenzimidazole were considerably less active than DRB. In single cycle experiments, the degree of inhibition of Lee virus multiplication by DRB in membrane cultures was not dependent on the amount of virus in the inoculum. This compound did not inactivate the infectivity of extracellular Lee virus, had no effect on virus-erythrocyte interaction, did not interfere with the adsorption of the virus by the host tissue, nor affect the release of newly formed virus from the membrane. The inhibitory effect of DRB on Lee virus multiplication, in contrast to that of 2,5-dimethylbenzimidazole, persisted after transfer of infected membranes into fresh culture medium not containing the compound. Both DRB and the 2,5-dimethyl compound caused 99 per cent inhibition of Lee virus multiplication without affecting oxygen uptake of the membrane. Tissue proliferation of membrane pieces in roller tube culture was not significantly affected by DRB at inhibitory concentration, whereas at equivalent concentration the 2,5-dimethyl compound did restrict cellular growth. At higher concentrations, both compounds caused retardation of cell proliferation. This effect was reversible on removal of either compound from the medium. The multiplication of several strains of influenza A and B viruses, i.e. Lee, MB, PR8, and FM1, was inhibited to the same degree by each of the two compounds; DRB was 35 times more active than the 2,5-dimethyl compound relative to each of the strains. DRB caused inhibition of Lee virus multiplication in intact embryonated chicken eggs and in mice without causing significant signs of toxicity in either host. Some of the implications of these findings are discussed in relation to the mechanism of the inhibition of influenza virus multiplication.

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HYDROLYSIS PRODUCTS OF PSEUDOVITAMIN B₁₂

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Pseudocoenzyme B12 and Adenosyl-Factor A: Electrochemical Synthesis and Spectroscopic Analysis of Two Natural B12 Coenzymes with Predominantly ‘Base-off' Constitution

Pseudocoenzyme B12 and Adenosyl-Factor A: Electrochemical Synthesis and Spectroscopic Analysis of Two Natural B12 Coenzymes with Predominantly ‘Base-off' Constitution

Native Corrinoids fromClostridium cochleariumAre Adeninylcobamides: Spectroscopic Analysis and Identification of Pseudovitamin B₁₂and Factor A

Inhibition of Influenza Virus Multiplication by N-Glycosides of Benzimidazoles

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HYDROLYSIS PRODUCTS OF PSEUDOVITAMIN B12

Cited by 50 publications

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Pseudocoenzyme B12 and Adenosyl-Factor A: Electrochemical Synthesis and Spectroscopic Analysis of Two Natural B12 Coenzymes with Predominantly ‘Base-off' Constitution

Pseudocoenzyme B12 and Adenosyl-Factor A: Electrochemical Synthesis and Spectroscopic Analysis of Two Natural B12 Coenzymes with Predominantly ‘Base-off' Constitution

Native Corrinoids fromClostridium cochleariumAre Adeninylcobamides: Spectroscopic Analysis and Identification of Pseudovitamin B12and Factor A

Inhibition of Influenza Virus Multiplication by N-Glycosides of Benzimidazoles

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HYDROLYSIS PRODUCTS OF PSEUDOVITAMIN B₁₂

Native Corrinoids fromClostridium cochleariumAre Adeninylcobamides: Spectroscopic Analysis and Identification of Pseudovitamin B₁₂and Factor A