N-Lipidated Amino Acids and Peptides Immobilized on Cellulose Able to Split Amide Bonds

Abstract

N-lipidated short peptides and amino acids immobilized on the cellulose were used ascatalysts cleaved amide bonds under biomimetic conditions. In order to select catalytically mostactive derivatives a library of 156 N-lipidated amino acids, dipeptides and tripeptides immobilizedon cellulose was obtained. The library was synthesized from serine, histidine and glutamic acidpeptides N-acylated with heptanoic, octanoic, hexadecanoic and (E)-octadec-9-enoic acids.Catalytic efficiency was monitored by spectrophotometric determination of p-nitroaniline formedby the hydrolysis of a 0.1 M solution of Z-Leu-NP. The most active 8 structures contained tripeptidefragment with 1-3 serine residues. It has been found that incorporation of metal ions into catalyticpockets increase the activity of the synzymes. The structures of the 17 most active catalysts selectedfrom the library of complexes obtained with Cu2+ ion varied from 16 derivatives complexed withZn2+ ion. For all of them, a very high reaction rate during the preliminary phase of measurementswas followed by a substantial slowdown after 1 h. The catalytic activity gradually diminished aftersubsequent re-use. HPLC analysis of amide bond splitting confirmed that substrate consumptionproceeded in two stages. In the preliminary stage 24–40% of the substrate was rapidly hydrolysedfollowed by the substantially lower reaction rate. Nevertheless, using the most competentsynzymes product of hydrolysis was formed with a yield of 60–83% after 48h under mild andstrictly biomimetic conditions.