Marie-José Blais

Bio: Marie-José Blais is an academic researcher from University of Poitiers. The author has contributed to research in topics: Copper & Succinimide. The author has an hindex of 7, co-authored 20 publications receiving 198 citations.

A new contribution to the determination of the complex equilibria of oxidised glutathione with proton and copper(II) in aqueous solution

Abstract: The stability constants of the complexes formed between copper(II) and oxidised glutathione have previously been determined In the present work, using identical experimental conditions, we have essentially confirmed the model previously proposed, above pH 5 However, for the range pH 2–5 we support a later model proposed by other workers which questioned the correctness of the earlier one

Copper complexes offer a physiological approach to treatment of chronic diseases.

Abstract: Publisher Summary This chapter discusses copper complexes that offer a physiological approach to the treatment of chronic diseases. Copper is recognized as an essential metalloelement just as sodium, potassium, magnesium, calcium, iron, zinc, chromium, vanadium, and manganese. Just as essential amino acids, essential fatty acids and essential cofactors (vitamins), essential metalloelements are required for normal metabolic processes but cannot be synthesized de novo, and daily dietary intake and absorption are required. The adult body contains between 1.4 mg (22 pmol) and 2.1 mg (33 pmol) of copper per kilogram of body weight while the infant body contains three times this amount, consistent with the fact that infant metabolic needs are that much greater than those of adults. The essentiality of copper is now understood as being based upon its recognized need for activation of copper-dependent enzymes. Complexed forms of copper also facilitate absorption, tissue distribution, and tissue utilization. In the nondisease state, these forms of copper account for the physiologic regulation of copper-dependent homeostatic processes. Consistent with the newly found role for copper in synthesis of neuroendocrine peptides, the copper complex of histidine has been found to increase the secretion of luteinizing hormone-releasing hormone (LH-RH) from granules of the median eminence.

Metal–amino acid chemistry. Weak interactions and related functions of side chain groups

Abstract: α-Amino acids are highly functional small molecules whose side chain groups are like prototypes of metal coordination and weak interactions in proteins. This perspective focuses on non-covalent or weak interactions of the side chain groups of amino acids, such as the charged groups of arginine and aspartic acid and the aromatic rings of tyrosine and tryptophan, in metal complexes in solution and in the solid state. The structure and function of small complexes exhibiting weak interactions and their biological relevance are described.

Basicity and Acidity of Azoles

Abstract: Publisher Summary This chapter provides a large collection of solution data and a thoroughly updated discussion of thermodynamic, kinetic, and structural results. This chapter covers aromatic azoles exclusively—that is, aromatic five-membered rings containing only carbon and nitrogen atoms, and their benzo derivatives. This chapter also discusses parent structure on theoretical grounds. One of the oldest methods to get insight into molecular structure, the study of acid-base properties, is today in rapid development. This is particularly true for the azoles. Gas phase studies of the acidity and basicity of azoles provides information on lone pair interactions, transmission of substituent effects in five-membered rings, relationships between acidity and basicity, aromatic substituent effects of nitrogen-linked derivatives and thermodynamic and kinetic parameters for proton transfer between nitrogen atoms in polyazoles. Because of the biological significance of some azoles (pyrrole, indole, imidazole, benzimidazole) and the consequences of acid–base equilibria in their functions, a continuous interest in the behavior in water is to be expected. In the case of N-unsubstituted imidazoles and pyrazoles, complexation of the pyridine-like nitrogen causes a considerable increase in the acidity of the pyrrolelike nitrogen.

The Chemistry of Hydantoins

Abstract: Publisher Summary This chapter reviews the chemistry of hydantoins. The hydantoins can be synthesized using amino acids, cyanate or thiocyanate salts, alkyl or aryl isocyanates and isothiocyanates, ureas, α-dicarbonyl compounds, Bucherer–Bergs and Read reactions, and cycloaddition reactions with heterocumulenes. The chapter also illustrates physicochemical studies on hydantoins. H-NMR, IR, and UV techniques are widely used to study ionization and tautomerism in hydantoins. Hydantoins are weak acids which owe their acidic character to dissociation of the proton bonded to the 3-nitrogen atom as this allows for maximum delocalization of charge in anion. The chapter also presents physicochemical studies on hydantoins using ultraviolet spectroscopy, mass spectrometry, infrared spectroscopy, nuclear magnetic resonance spectroscopy, crystal structure determinations, and quantum mechanical calculations. The reactivity of hydantoins and their derivatives are described further in the chapter. Hydantoins and thiohydantoins can react with nucleophilic and electrophilic as well as with other types of reagents. On protonation in a strongly acidic solution, hydantoin cations are formed. Hydantoins can easily be alkylated in the N-3 position by treatment with alkyl halides in an alkaline solution in protic or aprotic solvents. Other alkylating agents include dimethyl sulfate and diazomethane.