Abstract: Disclosed are new molecules, on a peptide-porphyrin base, with a low molecular weight (2000-5000 uma), optionally in covalent association with biomolecules, which are able to catalyse peroxidation, oxidation, hydroxylation, phenol nitration and inert compound epoxidation reactions, using clean reagents such as H2O2 in aqueous or water-alcohol solutions, with catalytic efficiency comparable or superior to that of natural enzymes. The compounds according to the invention can be used as catalysts in fine chemistry, in the control and decontamination of waters and laboratory diagnostics, and may be bonded and/or adsorbed on solid matrices or nanoparticles.