منابع مشابه
The assay of aromatic amino acid transaminations and keto acid oxidation by the enol borate-tautomerase method.
The enol tautomers of the aromatic oc-keto acids combine instantaneously and reversibly with borate to form complexes of a mixed ester-anhydride structure, thereby displacing the apparent keto-enol equilibrium in favor of the enol tautomer. The enol tautomer and its borate complex have strong absorption in the 300 ml* region (1). This strong absorption is the basis of the spectrophotometric met...
متن کاملProbing keto-enol tautomerism using photoelectron spectroscopy.
We theoretically investigate the mechanism of tautomerism in the gas-phase acetylacetone molecule. The minimum energy path between the enolone and diketo forms has been computed using the Nudged-Elastic Band (NEB) method within the density-functional theory (DFT) using the projector augmented-wave method and generalized gradient approximation in Perdew-Wang (PW91) parametrization. The lowest tr...
متن کاملThe a-Cyano-a-phenylacetic Acid Keto-Enol System. Flash Photolytic Generation of the Enol in Aqueous Solution and Determination of the Keto-Enol Equilibrium Constants and Acid Dissociation Constants Interrelating All Keto and Enol Forms in That Medium
The enol of a-cyano-a-phenylacetic acid was observed as a short-lived transient species formed upon flash photolytic generation of phenylcyanoketene by a photo-Wolff reaction of a-cyano-a-diazoacetophenone followed by hydration of the ketene. Rates of ketonization of the enol were measured in dilute hydrochloric acid solutions and acetic acid, biphosphate ion, tris(hydroxymethyl)methylamine, an...
متن کاملTautomerism of isoguanosine and solvent-induced keto-enol equilibrium.
Ultraviolet and infrared absorption spectroscopy, in aqueous and non-aqueous media, have been employed to study the tautomerism of 9-substituted isoguanines, including the nucleoside isoguanosine. With the aid of a series of model compounds, it was shown that 9-substituted isoguanines, and isoguanosine, in aqueous medium are predominantly in the form N (1) H, 2-keto-6-amino. In dioxane solution...
متن کاملComputational Studies of Photobiological Keto-Enol Reactions and Chromophores
This thesis presents computational chemistry studies of keto-enol reactions and chromophores of photobiological significance. The first part of the thesis is concerned with two protein-bound chromophores that, depending on the chemical conditions, can exist in a number of different ketonic and enolic forms. The first chromophore is astaxanthin, which occurs in the protein complex responsible fo...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1969
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)94366-8