Thermal decomposition and cobalt-carbon bond dissociation energies of organocobalamins: neopentyl-, (cyclopentylmethyl)-, (cyclohexylmethyl)-, (tetrahydrofurfuryl)- and ((tetrahydro-2H-pyryl)methyl)cobalamin
Studies on Vitamin B<sub>12</sub> and Related Compounds, 51 [1] Direct Syntheses of Alkylcobalamins from Alkanes and Vitamin B<sub>12r</sub> under "Oxidizing-Reducing" Conditions
作者:Abdussalam Maihub、Hui Bi Xu、Gerhard N. Schrauzer
DOI:10.1515/znb-1980-1122
日期:1980.11.1
n-alkylcobalamins from n-alkanes (C2→C10) and vitamin B12r are described. The compounds are formed under "oxidizing-reducing" conditions: Oxygen radicals (O2-, HOO·, and HO·) are generated from the reaction of O2 with reducing metal ions, notably V+3 (aq) and abstract hydrogen from the alkane substrates. The resulting alkyl radicals are captured by vitamin Bj2r with high efficiency to yield alkylcobalamins
Sacrificial Cobalt–Carbon Bond Homolysis in Coenzyme B<sub>12</sub> as a Cofactor Conservation Strategy
作者:Gregory C. Campanello、Markus Ruetz、Greg J. Dodge、Harsha Gouda、Aditi Gupta、Umar T. Twahir、Michelle M. Killian、David Watkins、David S. Rosenblatt、Thomas C. Brunold、Kurt Warncke、Janet L. Smith、Ruma Banerjee
DOI:10.1021/jacs.8b08659
日期:2018.10.17
intracellular trafficking pathway in humans is used to tailor vitaminB12 into its active cofactorforms, and to deliver it to two known B12-dependent enzymes. Herein, we report an unexpected strategy for cellular retention of B12, an essential and reactive cofactor. If methylmalonyl-CoA mutase is unavailable to accept the coenzyme B12 product of adenosyltransferase, the latter catalyzes homolytic