Hydrolytic Metalloenzyme Models

Chiral metallomicellar supramolecular systems composed of lipophilic L-histidinol have been investigated for their catalytic activities and enantioselectivities in the hydrolysis of N-protected alpha-amino acid esters. Kinetic evidence suggests that the mechanism of the deacylation promoted by ligand 4a with a hydroxyl group and 2a lacking a hydroxyl group is different. The apparent pK(a) of Zn2+ -4a is 6.8 in the micelllar aggregate. The highest enantioselectivity in hydrolysis of R(S)-C-12-Leu-PNP (k(S)/k(R) = 3.01) was obtained with 4a-Zn2+ as catalyst. (C) 2003 Elsevier Science B.V. All rights reserved.