Title |
Assessing the microcystins concentration through optimized protein phosphatase inhibition assay in environmental samples |
Author |
Kyoung-Hee Oh1, Kung-Min Beak1, Yuna Shin2, and Young-Cheol Cho1* |
Address |
1Department of Environmental Engineering, Chungbuk National University, Cheongju 28644, Republic of Korea, 2Water Quality Assessment Research Division, National Institute of Environmental Research, Incheon 22689, Republic of Korea |
Bibliography |
Journal of Microbiology, 60(6),602-609, 2022,
|
DOI |
10.1007/s12275-022-2020-4
|
Key Words |
concentration of methanol, limit of quantitation,
microcystins, protein phosphatase inhibition assay, reaction
terminator |
Abstract |
Protein phosphatase (PPase) inhibition assay (PPIA) is widely
used to analyze the concentration of microcystins (MCs) because
it is comparatively less expensive and faster than other
assays. This study aimed to optimize the PPIA by determining
a suitable reaction terminator and an optimal methanol
concentration in the sample. The most suitable reaction time
was 90 min, with the corresponding methanol concentration
in the sample being 15% or less. When p-nitrophenyl phosphate
(pNPP) was used as a substrate, copper chloride solution
was suitably used as a reaction terminator, and when 4-
methylumbelliferyl phosphate (MUP) was used, a glycine buffer
not only increased the measurement sensitivity of the reaction
product but also terminated the enzymatic reaction.
When PPase 1 and MUP were used as an enzyme and a substrate,
respectively, the limit of quantitation for MC-leucine/
arginine (LR) was 0.02 μg/L, whereas it was 0.1 μg/L when
pNPP was used as a substrate. The proposed method facilitated
the measurement of MC-LR concentration without
additional pretreatments, such as concentration or purification;
therefore, this method was suitable and feasible for the
continuous monitoring of MCs in drinking water. |