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Many acids can function as sources for the protons. Acid used for acid catalysis include hydrofluoric acid (in the alkylation process), phosphoric acid, toluenesulfonic acid, polystyrene sulfonate, heteropoly acids, zeolites. Strong acids catalyze the hydrolysis and transesterification of esters, e.g. for processing fats into biodiesel. In ...
DNA glycosylases are a family of enzymes involved in base excision repair, classified under EC number EC 3.2.2. Base excision repair is the mechanism by which damaged bases in DNA are removed and replaced.
An acid-base-nucleophile triad is a common motif for generating a nucleophilic residue for covalent catalysis. The residues form a charge-relay network to polarise and activate the nucleophile, which attacks the substrate , forming a covalent intermediate which is then hydrolysed to release the product and regenerate free enzyme.
Ascorbate peroxidase (or L-ascorbate peroxidase, APX or APEX) (EC 1.11.1.11) is an enzyme that catalyzes the chemical reaction. L-ascorbate + H 2 O 2 dehydroascorbate + 2 H 2 O. It is a member of the family of heme-containing peroxidases.
A key feature of enzyme catalysis over many non-biological catalysis, is that both acid and base catalysis can be combined in the same reaction. In many abiotic systems, acids (large [H+]) or bases ( large concentration H+ sinks, or species with electron pairs) can increase the rate of the reaction; but of course the environment can only have ...
Two common modes of Lewis acid catalysis in reactions with polar mechanisms. In reactions with polar mechanisms, Lewis acid catalysis often involves binding of the catalyst to Lewis basic heteroatoms and withdrawing electron density, which in turn facilitates heterolytic bond cleavage (in the case of Friedel-Crafts reaction) or directly activates the substrate toward nucleophilic attack (in ...
The research group of John E. Walker, then at the MRC Laboratory of Molecular Biology in Cambridge, crystallized the F 1 catalytic-domain of ATP synthase. The structure, at the time the largest asymmetric protein structure known, indicated that Boyer's rotary-catalysis model was, in essence, correct.
In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell.The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical reactions catalyzed by enzymes.