title: Polyamino acids as synthetic enzymes: mechanism, applications and relevance to prebiotic catalysis.
abstract: Polyamino acids, such as polyleucine, behave as synthetic enzymes in the asymmetric epoxidation of chalcone and other electron-deficient alkenes (the Julià-Colonna reaction). The influences of reaction conditions, of the molecular structure of the catalysts and of the scaling-up of the process on the enantioselectivity of the reaction have been determined. The kinetics and mechanism have been investigated using a soluble PEG-polyleucine conjugate, which behaves in a similar way to an enzyme, showing saturation kinetics for both chalcone and HOO-. Enantioselective catalysis is achieved with peptides with as few as five residues and scalemic catalysts show high chiral amplification. Here, we discuss the relevance of these-enzyme like catalysts to prebiotic processes, such as the role of small peptides in the formation of optically active cyanohydrins.
authors.affiliation: Istituto di Chimica del Riconoscimento Molecolare, CNR, Via Mario Bianco 9, 20131 Milano, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Carrea
authors.forename: Stefano
authors.initials: S
authors.lastname: Colonna
authors.forename: David R
authors.initials: DR
authors.lastname: Kelly
authors.forename: Antonio
authors.initials: A
authors.lastname: Lazcano
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ottolina
authors.forename: Stanley M
authors.initials: SM
authors.lastname: Roberts
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D004798:Enzymes / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D004798:Enzymes