Abstract: The invention relates to peptide compositions for use in the preparation of pharmaceutical compositions against hepatitis C virus, as well as corresponding methods.

Abstract: This invention relates to a process for the preparation of free L .alpha.-amino acids by the complete conversion of their D antipodes taken individually or possibly in racemic mixtures.The process according to the present invention is characterized in that the D antipodes of an ester of said .alpha.-amino acid is racemized in the presence of a chemical catalyst formed by at least one aromatic aldehyde corresponding to the general formula: ##STR1## wherein: Ar represents an aromatic ring optionally containing a heteroatom, such as nitrogen, andB represents a basic function,to produce a mixture in dynamic equilibrium of the two forms D and L of said ester, the ester which is present in the L form is hydrolyzed enzymatically and irreversibly to produce the corresponding stereostable L .alpha.-amino acid, said stages of chemical racemization and of enzymatic hydrolysis being carried out under identical reaction conditions, and the free L .alpha.-amino acid is recovered.