Model studies of coenzyme B12 dependent diol dehydratase. 2. A kinetic and mechanistic study focusing upon the cobalt participation or nonparticipation question

1983 ◽  
Vol 105 (26) ◽  
pp. 7605-7617 ◽  
Author(s):  
Richard G. Finke ◽  
David A. Schiraldi
Keyword(s):  
Mechanistic Study ◽  
Coenzyme B12 ◽  
Model Studies ◽  
Diol Dehydratase

Model studies of coenzyme B12 dependent diol dehydratase. 1. Synthetic, physical property, and product studies of two key, cobalt-bound, putative diol dehydratase intermediates

1983 ◽  
Vol 105 (26) ◽  
pp. 7592-7604 ◽  
Author(s):  
Richard G. Finke ◽  
William P. McKenna ◽  
David A. Schiraldi ◽  
Brad L. Smith ◽  
Cortlandt Pierpont
Keyword(s):  
Physical Property ◽  
Coenzyme B12 ◽  
Model Studies ◽  
Diol Dehydratase

Concerning the intermediacy of organic radicals in vitamin B 12 -dependent enzymic reactions

1985 ◽  
Vol 311 (1152) ◽  
pp. 531-544 ◽  
Keyword(s):  
Carbon Atom ◽  
Crystal Structures ◽  
Organic Radicals ◽  
Vitamin B ◽  
Molecular Rearrangements ◽  
Alkyl Radicals ◽  
Model Studies ◽  
Diol Dehydratase ◽  
Vitamin B 12

The vitamin B 12 coenzyme adenosylcobalamin assists the enzymic catalysis of molecular rearrangements of the type in which the migrating group X can be OH, NH 2 or a suitable substituted carbon atom such as C (=CH 2 )CO 2 H. This paper discusses evidence for the participation of organic radicals as intermediates in these reactions. Theoretical and model studies supporting the intermediacy of radicals in the reactions catalysed by the enzymes diol dehydratase and α-methyleneglutarate mutase are described. For the model studies, alkyl radicals, alkylcobaloximes (alkyl represents, for example, ethoxycarbonyl substituted, but-3-enyl and cyclopropylmethyl) and also dihydroxyalkylcobalamins have been investigated. The Co-C α -C β angle of 125° in adenosylcobalamin is shown to be an ‘especial’ angle by analysis of the crystal structures of R - and S -2,3-dihydroxypropylcobalamin.

Mechanism-based Inactivation of Coenzyme B12-dependent Diol Dehydratase by 3-Unsaturated 1,2-Diols and Thioglycerol

2008 ◽  
Vol 144 (4) ◽  
pp. 437-446 ◽  
Author(s):  
T. Toraya ◽  
N. Tamura ◽  
T. Watanabe ◽  
M. Yamanishi ◽  
N. Hieda ◽  
...  
Keyword(s):  
Coenzyme B12 ◽  
Diol Dehydratase
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