Detection and Quantification of Carboxylesterase 2 Activity by Capillary Electrophoresis

Abstract

The purpose of this study was to develop an analytical method to quantify the relative activities of carboxylesterases (CESs) in biological samples. Taking the advantage of loperamide, a specific carboxylesterase 2 (CES2) inhibitor, and bis-p-nitrophenyl phosphate (BNPP), an irreversible CESs inhibitor, we propose for the first time a capillary electrophoresis (CE) method that enables detecting and distinguishing CES2 activity from other CESs in complex biological samples. The capillary electrophoresis method proved to be fast, simple, repeatable, and applicable to the measurement of the specific activity of CESs. The method was successfully applied to the evaluation of human cells overexpressing human carboxylesterase 2 (hCE-2) and to several mammalian sera, using extremely small amounts of samples in comparison with traditional spectrophotometric methods. The same rationale can be applied to establish methods for determining the activity of other isoenzymes, using the appropriate specific inhibitors.

Comparison of in vitro methods for carboxylesterase activity determination in immortalized cells representative of the intestine, liver and kidney

“…These concentrations were confirmed to be sufficient for inhibition of up to 50 ng of hCES2 and 50 ng of HCES2 plus 12.5 ng of CES1 as previously reported [13]. Both inhibitors were prepared in DMSO.…”

“…Different methods have been developed for studying the activity of hCESs in cell lysates [13] as well as in living cells [17]. Hydrolysis by hCES is, in fact, most commonly tested in vitro using tissue homogenates, microsomes or cell lysates [21].…”

A Minireview of Recent Reported Carboxylesterase Fluorescent Probes: Design and Biological Applications

“…Carboxylesterases have many isozymes and are classified into six main groups (CES1–CES6) as well as several subgroups. Although these isozymes share 40–50 % similar amino acid sequences, they still display differences in tissue distribution and distinct substrate . Actually, CES1 and CES2 are the major subtypes of CESs in the human body, and CES1 share 48 % sequence homology with CES2.…”

A compact short‐capillary based high‐speed capillary electrophoresis bioanalyzer

“…CE, as a high resolution and rapid analysis technique, has been widely used in multidimensional separations , in vivo chemical monitoring , and reaction dynamics studies . High‐speed CE, by using high electric field strengths, short separation distances, and narrow sample plugs, has advantages of high‐speed and high‐efficiency CE separations over traditional CE systems , and has been applied in analysis of various samples including amino acids , carbohydrates , proteins , DNA fragments , enzymes , and other small molecule components in explosive residues, drugs, and body fluids.…”