Curcumin, derived from Curcuma longa plant has been shown to exhibit antioxidant, antiinflammatory, antiviral, antibacterial, antifungal, and anticancer activities and thus has a potential against various malignant diseases, diabetes, allergies, arthritis, Alzheimer’s disease, and other chronic illnesses [1–3]. In the light of these promising propertiesseveral questions need to be answered in o...

The present paper describes a new enzyme from animal tissues which catalyzes the keto-enol tautomeriaation of the phenylpyruvic acids. Preliminary accounts of this tautomerase have been published (1, 2). The enzyme has not yet proved to be essential in any biological reaction, but a physiological role may be expected since specific tautomers of a-keto acids are substrates or products in some re...

In photoinduced molecular reaction dynamics, the effects of electronic charge redistribution can lead to multiple pathways that are determined by the nature of the initial structures involved and the environment the molecule of interest is studied in. The β-diketones are a common example of this complexity. They show keto-enol tautomerism that is almost totally shifted toward the enolic form. H...

Tautomerism in organic chemistry has been extensively studied in condensed phase by spectrometric methods, mainly by IR and NMR techniques. Mass spectrometry studies start 40 years ago but just recently it has been recognized the importance of the mass spectral data for the study of tautomerism in the gas phase. Mass spectrometry can provide valuable information in regard to tautomeric equilibr...

Studies of the non-enzymatic decarboxylation of /3-keto acids have shown that it is the keto form of the 8-keto acid which loses CO2 to form an enol of the product. This was demonstrated for dimethylacetoacetic acid by Pedersen (1) and for dimethyloxalacetic acid by Steinberger and Westheimer (2). These latter authors studied the catalytic effect of metal ions on the decarboxylation reaction an...