Dynamic Combinatorial Thiolester Libraries for EfficientCatalytic Self‐Screening of Hydrolase Substrates

Dynamic combinatorial thiolester libraries were efficiently generated from pools of thiols and acyl functionalities through reversible transthiolesterification in aqueous media at neutral pH. The dynamic features of the library generation were investigated, and the libraries were screened against acetylcholinesterase, clearly demonstrating the catalytic self‐screening of its substrates from the constituents. Acetyl‐ and propionylthiocholine were easily identified as the best substrates for the enzyme, whereas other constituents showed lower efficiency or were inactive. A range of hydrolases was furthermore screened for rapid substrate identification, clearly demonstrating the differences in selectivity. The results show that transthiolesterification is a useful method to generate dynamic libraries, and that the catalytic self‐screening concept is highly valuable for substrate identification. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)