Andrée Marquet and her collaborators have been interested in reaction mechanisms in organic chemistry, in particular those involving carbanions (enolates, alpha anions of sulfoxides), and have used the results of these studies in synthesis, for example for total synthesis of biotin.
She then turned to mechanistic enzymology, applying the approach used in organic chemistry to the functioning of enzymes.
The main areas covered are :
*    steroid biochemistry: inhibition of the biosynthesis of aldosterone (among the various compounds synthesized and tested, 18-vinyl progesterone proved to be an excellent inhibitor of Cytochrome P450 involved in the last stage of this biosynthesis, making this molecule a potential hypotensor.
*    the mechanism of action of vitamin K, an essential cofactor in the cascade of blood coagulation reactions.
*    the biotin biosynthesis pathway: the mechanism of several of the enzymes involved has been deciphered and various inhibitors have been designed and synthesized. A particularly difficult problem to which Andrée Marquet and her team have made a decisive contribution is that of the mechanism of biotin synthase, which catalyses the final step.
They have shown that it belongs to the newly discovered family of proteins (Fe-S) dependent on S-Adenosylmethionine, catalysing radical reactions. This is a family that opens a new chapter in enzymology.
Another field of activity of the laboratory, the result of a collaboration with the neurobiology laboratory of the Collège de France (Prof. Jacques Glovinski) concerns the activity of a family of peptide neurotransmitters, the tachykinins.