| Autor: |
Bekhit M; Department of Chemistry , University of Texas at San Antonio , One UTSA Circle , San Antonio , Texas 78249 , United States., Gorski W; Department of Chemistry , University of Texas at San Antonio , One UTSA Circle , San Antonio , Texas 78249 , United States. |
| Jazyk: |
angličtina |
| Zdroj: |
Analytical chemistry [Anal Chem] 2019 Feb 19; Vol. 91 (4), pp. 3163-3169. Date of Electronic Publication: 2019 Feb 07. |
| DOI: |
10.1021/acs.analchem.8b05855 |
| Abstrakt: |
Strategies to detect and characterize myeloperoxidase (MPO) are needed, given that this "split personality" enzyme kills harmful microorganisms but also damages a host tissue. Here, we describe electrochemical approaches to measure MPO by using the pseudohalogenation (MPO/SCN - /H 2 O 2 ) and catalase-like (MPO/H 2 O 2 ) cycles. Their kinetics were determined by monitoring the consumption of H 2 O 2 with a nitrogen-doped carbon nanotubes (N-CNT) electrode, which could detect 0.50 μM H 2 O 2 at -0.20 V. The unique design of internally calibrated electrochemical continuous enzyme assay (ICECEA) and electrode stability allowed use of one N-CNT electrode for over half a year to reliably determine MPO. The kinetic measurements showed that (a) SCN - did not affect the affinity of MPO for H 2 O 2 , (b) catalase-like cycle was slower, and (c) MPO retained enzymatically active conformation after complexation with its antibody Ab both in a solution and on the surface of an antibody dipstick (d/Ab). The homogeneous assays could detect 5.2 μg L -1 MPO (35 pM) via a faster cycle. The heterogeneous immunoassays with the capture of MPO on d/Ab could detect 60 μg L -1 , which was suitable for the accurate detection of MPO in human saliva (101% recovery). Replacing a detection antibody of ELISA with ICECEA as a signal transducer for immunoassays offers a rapid method for the selective determination of enzymes; for example, time of MPO quantification was cut from 3-4 h (sandwich ELISA) to ∼20 min (ICECEA-dipstick). |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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