Chapter 11

Biological Aspects of Metal Enolates


Li-June Ming

Department of Chemistry and Institute for Biomolecular Science

University of South Florida

4202 E. Fowler Avenue, CHE205

Tampa, Florida 33620-5250




my mom and Shu-Ching

for their endless love and support throughout my career





          A. Scope of the Chapter

          B. Enol-containing Natural Products

          C. Enols and Enolates in Chemical Reactions

          D. Stabilization of the Enol Functional Group in Biological Processes


III. Metal Enolates in Biological Systems

          A. Metal Complexes of Enolates

          B. Enol-containing Biochemicals and Pharmaceuticals and Their Metal Complexes

                 1. Biochemicals

                        a. Ascorbic acid

                        b. Flavonoids

                        c. Mimosine and analogues

                        d. Kojic acid and pyranones

                        e. Furanones

                        f. Quinone derivatives

                        g. Tropolones

                 2. Pharmaceuticals

                        a. Antibiotic tetracyclines

                        b. Oxicam anti-inflammatory drugs

                        c. Deferiprone for iron overload

                        d. Antimalarial hydroxynaphthoquinones and analogues

                 3. Miscellaneous applications of metal enolates

                        a. Antitumor agents

                        b. Biosensors and imaging agents



          A. Enols and Associated Enzymes in Glycolysis and Other Sugar Metabolisms

                 1. Enols in ketose–aldose isomerization

                 2. Stabilization of enol intermediates in aldolases and epimerases

                 3. Enolates in triosephosphate isomerase

                 4. Role of metal ions in enolases and the enolase superfamily

                 5. Metal–enolate interaction in pyruvate kinase

          B. Rubisco

          C. Ascorbic Acid Biosynthesis and Biological Roles

          D. Amine Oxidases

          E. Quercetin 2,5-Dioxygenase

          F. Acireductone Dioxygenase

          G. b-Diketone-cleaving Enzymes

                 1. Hydrolytic cleavage

                 2. Oxidative cleavage

          H. TetA and Tetracycline Resistance

          I. Enols in Enzyme Inhibition