Electron paramagnetic resonance spectra of some vitamin B12 derivatives

Cockle, Stephen A.; Hill, H. A. O.; Pratt, J. M.; Williams, R. J. P.

doi:10.1016/0304-4165(69)90346-8

Cited by 33 publications

(9 citation statements)

References 2 publications

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“…the cobalt coupling constants are in considerable disagreement with our values. In a preliminary note which appeared after submission of our paper, Cockle et al (1969) give coupling constants which agree well with our values (after conversion to the same units), but in addition they find a dependence on the nature of the reducing system. They suggest that the substance referred to as factor Br by Schrauzer and Lee (1968) has a nitrogenous base as fifth ligand, which would explain why the coupling constant is not appropriate for aquocob(II)inamide or cyanocob(II)inamide.…”

Section: Discussionsupporting

confidence: 83%

Electron paramagnetic resonance studies of cob(II)alamin and cob(II)inamides

Bayston¹,

Looney²,

Pilbrow³

et al. 1970

Biochemistry

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Although the water molecule in the fifth coordination position of diaquocob(II1)inamide is easily replaced by imidazole-or pyridine-like molecules, the other aquo group is replaced less readily. On reduction to the cobaltous state the group in the sixth coordination position detaches. The bond to the fifth ligand is weakened, so that in general there is some replacement by solvent, but ligands such as imidazole

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Section: Discussionsupporting

confidence: 83%

Electron paramagnetic resonance studies of cob(II)alamin and cob(II)inamides

Bayston¹,

Looney²,

Pilbrow³

et al. 1970

Biochemistry

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“…One of the physical methods that had been used was electron paramagnetic resonance (EPR) spectroscopy [ 6 ], valuable for the low-spin d 7 cobalt(II) derivatives. It was quite a surprise to find, in the holoenzyme diol-dehydratase, the system gave rise [ 7 ] to a striking EPR spectrum in the presence of the substrate that was not obviously related to that of an unaltered Co(II) form .…”

Section: Vitamin B 12mentioning

confidence: 99%

Bringing inorganic chemistry to life with inspiration from R. J. P. Williams

Hill¹,

Sadler

2016

J Biol Inorg Chem

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Our appreciation of the scholarly ideas and thinking of Bob Williams is illustrated here by a few of the areas in which he inspired us. His journey to bring inorganic chemistry to life began with an early interest in analytical chemistry, rationalising the relative stabilities of metal coordination complexes (The Irving-Williams Series), and elucidating the organometallic redox chemistry of vitamin B12. He (and Vallee) recognised that metal ions are in energised (entatic) states in proteins and enzymes, which themselves are dynamic structures of rods and springs. He played a key role in helping Rosenberg to pave the road toward the clinic for the anticancer drug cisplatin. He believed that evolution is not just dependent on DNA, but also on the metallome. Organisms and the environment are one system: does DNA code directly for all the essential elements of life?

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“…The spectrum for cob(II)alamin in the solid state shows much less hyperfine structure (Yamada et al, 1966) and a frozen aqueous solution gives a spectrum showing little structure when other solutes are absent (Hogenkamp et al, 1963). However, spectra with more structure have been reported for frozen solutions of cob(II)alamin containing other solutes or solvents by Schrauzer and Lee (1968), Cockle et al (1969), andBayston et al (1970). Seven of the lines of the highfield part of the spectrum can be clearly distinguished and several, but not all, of these lines are resolved into triplets.…”

Section: Cmp Gmp Ampmentioning

confidence: 99%

“…The hyperfine coupling constant, A,|Co, obtained from A agrees with published values for cob(II)alamin (103 X 10-4 cm"1 in the presence of cysteine and gluthathione). The splitting of the high-field lines into triplets is due to interaction of the electron with a nitrogen nucleus (7=1) and the work of Schrauzer and Lee (1968), Cockle et al (1969), and Bayston et al (1970 indicate that the coupling is to the N3-nitrogen of dimethylbenzimidazole. The A!…”

Section: Cmp Gmp Ampmentioning

confidence: 99%