EC Number |
Reaction |
Reference |
---|
4.2.1.28 | propane-1,2-diol = propanal + H2O |
binding of the substrate to the active site converts a hexacoordinated complex of K+ into the heptacoordinated one. A relatively large binding energy is released upon coordination of the two hydroxyl groups to K+, displacing a sixth ligand, H2O. Interaction of the coenzyme with the enzyme cleaves its Co-C bond, forming an adenosyl radical and cob(II)alamin. The radical abstracts the pro-S hydrogen of the S-enantiomer forming a substrate-derived radical and 5'-deoxyadenosine. The substrate-radical undergoes the 1,2-shift of the hydroxyl group, forming a product-derived gem-diol radical. The C2 of the product radical, abstracts a hydrogen back from deoxyadenosine with inversion of the configuration of C2, producing a 1,1-gem-diol, which undergoes dehydration, forming propionaldehyde and H2O |
653948 |
4.2.1.28 | propane-1,2-diol = propanal + H2O |
enzymatic radical catalysis, with adenosylcobalamin, coenzyme B12, as a cofactor. Dehydration of 1,2-diols to the corresponding aldehydes. The substrate and an essential potassium ion are located inside a betaalpha8 barrel. Two hydroxyl groups of the substrate coordinate directly to the potassium ion which binds to the negatively charged inner part of the cavity. Cobalamin bound covers the cavity to isolate the active site from the solvent. The initial migration of the hydroxyl group is stereospecific and the dehydration of a gem-diol undergoes steric control by the enzyme |
650799 |
4.2.1.28 | propane-1,2-diol = propanal + H2O |
general mechanism and stereochemistry, role of coenzyme in OH-group transfer, mechanism of overall reaction, role of free radicals during reaction, studies with coenzyme analogues |
5614, 5623 |
4.2.1.28 | propane-1,2-diol = propanal + H2O |
mechanism |
5623 |
4.2.1.28 | propane-1,2-diol = propanal + H2O |
mechanism: group migration involved, stereospecificity: replacement of C2-OH-group proceeds with inversion of configuration of both isomers, mechanism of hydrogen transfer, role of cobalt: dissociation of C-Co bond of the coenzyme and Co-binding to substrate |
5611 |
4.2.1.28 | propane-1,2-diol = propanal + H2O |
minimal mechanism for AdoCbl-dependent diol dehydratase involving the cob(II)alamin cofactor and active-site structure of the enzyme, overview |
696252 |
4.2.1.28 | propane-1,2-diol = propanal + H2O |
possible role of sulfhydryl groups |
5612 |
4.2.1.28 | propane-1,2-diol = propanal + H2O |
radical mechanism involved |
5628, 5636 |
4.2.1.28 | propane-1,2-diol = propanal + H2O |
radical mechanism. Abstraction of a hydrogen atom from C1 of the substrate by the 5'-deoxyadenosyl radical produces a substrate radical which undergoes further transformation into the radical precursor of hydrated propionaldehyde. If dehydration of the radical is by acid catalysis, a resonance-stabilized radical cationic intermediate is formed. The radical cation is then hydrated to the radical precursor of propionaldehyde hydrate. If base catalysis takes place, a ketyl radical is initially generated, and it eliminates hydroxide to form a resonance-stabilized aldehyde radical. Addition of hydroxide to the aldehydic group generates the radical precursor to propionaldehyde hydrate. The planar cationic radical from acid-catalyzed dehydration can lose a proton to form the semidione radical. In the base-catalyzed dehydration, the ketyl radical can eliminate hydroxide to form the semidione radical |
649991 |
4.2.1.28 | propane-1,2-diol = propanal + H2O |
reaction mechanism, quantum mechanical/molecular mechanical, QM/MM, modeling of diol dehydratase based on the crystal structure of diol dehydratase-adeninylpentylcobalamin complex, overview. The hydrogen recombination is the rate-determining step for the overall reaction |
715171 |