Polyamino acids as synthetic enzymes: mechanism, applications and relevance to prebiotic catalysis.
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.
Carrea
Giacomo
G
Istituto di Chimica del Riconoscimento Molecolare, CNR, Via Mario Bianco 9, 20131 Milano, Italy.
Colonna
Stefano
S
Kelly
David R
DR
Lazcano
Antonio
A
Ottolina
Gianluca
G
Roberts
Stanley M
SM
D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D004798:Enzymes / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D013237:Stereoisomerism
D000596:Amino Acids; D004798:Enzymes