Preparation of a PTE simulacrum based on surface
molecular imprinting
*
Yong Guo, Ying Yang, Tian Ying Guo
Key Laboratory of Functional Polymer Materials, Ministry of Education, Institute of Polymer Chemistry,
Nankai University, Tianjin 300071, China
Received 23 August 2010
Available online 15 January 2011
Abstract
Firstly, we synthesized N-methacryloyl-histidine monomer and N-methacryloyl-histidine-Cu2+ complex (MAH-Cu2+). Then the
molecular imprinting polymers (MIP) has been prepared by surface grafting on uniform polystyrene (PS) core using reversible
addition-fragmentation transfer polymerization (RAFT) with MAH-Cu2+ as the functional monomer, methyl paraoxon as the
template to simulate phosphotriesterase (PTE). Finally, we have investigated the catalytic hydrolytic activities of MIP and non-
imprinting polymers (NIP) to the template methyl paraoxon and the template analogue ethyl paraoxon respectively by UV
spectrophotometry. The results showed that the catalytic hydrolytic activity of MIP to the template methyl paraoxon was highest and
the value of k is 8.67 Â 10À5 mmol LÀ1 minÀ1, 3.89-fold higher than MIP to the template analogue ethyl paraoxon, 2.79-fold higher
than NIP to the template methyl paraoxon. The KM, rm of MIP are also determined, and KM = 3.95 Â 10À4 mol/L, rm = 2.12 mmol/
min. The MIP can be reused with only lose 7% of catalytic activity for four cycles.
# 2010 Tian Ying Guo. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
Keywords: Molecular imprinting; Surface grafting; Catalytic hydrolysis; Paraoxon
Organophosphate compounds are the most widely used herbicide and insecticide in agriculture, their long-term
accumulation in the environment will cause a very serious ecological threat to humans and other animals, and the
paraoxon is one of a kind commonly used. Therefore from the perspective of environmental governance that find a clean
technology to remove organophosphate compounds is very urgent. Paraoxon hydrolysis equation shown as Scheme 1.
Phosphotriesterase (PTE) is a natural zinc metalloenzyme that catalyzes the hydrolysis of an extensive array of
organophosphate pesticides (such as paraoxon, parathion and coumaphos) and mammalian acetylcholinesterase nerve
agents (like soman and sarin) [1–3]. Although PTE can quickly and efficiently catalyze the hydrolysis of
organophosphate, however, due to its preparation cumbersome, expensive, cannot resist high temperature, poor
stability, so its application subject to a certain extent. But the molecular imprinting catalyst simulated PTE is the
perfect replacement.
In this work, for the first time, we prepared imprinted mimic enzymes with hydrophobic PS core and hydrogel shell
using RAFT technique, it has good recognized performance, can be reused with only lose 7% of catalytic activity for
four cycles, most importantly, it can be applied to water system.
* Corresponding author.
1001-8417/$ – see front matter # 2010 Tian Ying Guo. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.