Evaluation of pesticide and heavy metal toxicity using immobilized enzyme alkaline phosphatase with an electrochemical biosensor

Kee Shyuan Loh, Yook Heng Lee, Musa Ahmad, S. A. Aziz, Z. Ishak

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13 Citations (Scopus)

Abstract

An bioelectrochemical sensor or biosensor based on the inhibition of the enzyme Alkaline Phosphatase (ALP) has been investigated for the screening of several environmental toxicants. The biosensor was constructed by immobilizing ALP in a hybrid sol-gel/chitosan film that was deposited on the surface of a screen-printed carbon paste electrode (SPE). The inhibition was measured via the catalytic hydrolysis of ascorbic acid 2-phosphate (AA2P) by the enzyme to produce ascorbic acid, Oxidation of this product was monitored amperometrically and the current change was then related to ALP activity. Toxicity of herbicides (2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), insecticides (caxbofuran and α-endosulfan) and heavy metals (Hg2+, Cd2+, Ag2+, Zn2+ and Cu2+) towards the biosensor were evaluated. Various degrees of inhibition of ALP occurred when the biosensor was exposed to herbicides and heavy metals. This resulted in a lower acid ascorbic production by the enzyme from the substrate, thus a decrease in the current response of the biosensor. The herbicides 2,4-D and 2,4,5-T showed the largest inhibition effect on ALP with linear response range of 1-60 μg L-1 (R = 0.92). The maximum inhibitions caused by 2,4-D and 2,4,5-T were 46 and 30%, respectively. Heavy metals caused inhibition on ALP at the higher concentration range of mg L-1. Thus, the biosensor may be useful for the screening of chlorophenoxyacetic acid herbicides even in the presence of other environmental toxicants.

Original languageEnglish
Pages (from-to)359-365
Number of pages7
JournalAsian Journal of Biochemistry
Volume3
Issue number6
DOIs
Publication statusPublished - 2008

Fingerprint

Immobilized Enzymes
Biosensing Techniques
Heavy Metals
2,4,5-Trichlorophenoxyacetic Acid
Pesticides
Biosensors
Alkaline Phosphatase
Toxicity
2,4-Dichlorophenoxyacetic Acid
Herbicides
Ascorbic Acid
Screening
Enzymes
Endosulfan
Chitosan
Polymethyl Methacrylate
Insecticides
Ointments
Sol-gels
Heavy Metal Toxicity

Keywords

  • Electrochemical biosensor
  • Enzyme inhibition
  • Herbicide
  • Toxic metal

ASJC Scopus subject areas

  • Biochemistry
  • Biochemistry, medical

Cite this

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title = "Evaluation of pesticide and heavy metal toxicity using immobilized enzyme alkaline phosphatase with an electrochemical biosensor",
abstract = "An bioelectrochemical sensor or biosensor based on the inhibition of the enzyme Alkaline Phosphatase (ALP) has been investigated for the screening of several environmental toxicants. The biosensor was constructed by immobilizing ALP in a hybrid sol-gel/chitosan film that was deposited on the surface of a screen-printed carbon paste electrode (SPE). The inhibition was measured via the catalytic hydrolysis of ascorbic acid 2-phosphate (AA2P) by the enzyme to produce ascorbic acid, Oxidation of this product was monitored amperometrically and the current change was then related to ALP activity. Toxicity of herbicides (2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), insecticides (caxbofuran and α-endosulfan) and heavy metals (Hg2+, Cd2+, Ag2+, Zn2+ and Cu2+) towards the biosensor were evaluated. Various degrees of inhibition of ALP occurred when the biosensor was exposed to herbicides and heavy metals. This resulted in a lower acid ascorbic production by the enzyme from the substrate, thus a decrease in the current response of the biosensor. The herbicides 2,4-D and 2,4,5-T showed the largest inhibition effect on ALP with linear response range of 1-60 μg L-1 (R = 0.92). The maximum inhibitions caused by 2,4-D and 2,4,5-T were 46 and 30{\%}, respectively. Heavy metals caused inhibition on ALP at the higher concentration range of mg L-1. Thus, the biosensor may be useful for the screening of chlorophenoxyacetic acid herbicides even in the presence of other environmental toxicants.",
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author = "Loh, {Kee Shyuan} and Lee, {Yook Heng} and Musa Ahmad and Aziz, {S. A.} and Z. Ishak",
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T1 - Evaluation of pesticide and heavy metal toxicity using immobilized enzyme alkaline phosphatase with an electrochemical biosensor

AU - Loh, Kee Shyuan

AU - Lee, Yook Heng

AU - Ahmad, Musa

AU - Aziz, S. A.

AU - Ishak, Z.

PY - 2008

Y1 - 2008

N2 - An bioelectrochemical sensor or biosensor based on the inhibition of the enzyme Alkaline Phosphatase (ALP) has been investigated for the screening of several environmental toxicants. The biosensor was constructed by immobilizing ALP in a hybrid sol-gel/chitosan film that was deposited on the surface of a screen-printed carbon paste electrode (SPE). The inhibition was measured via the catalytic hydrolysis of ascorbic acid 2-phosphate (AA2P) by the enzyme to produce ascorbic acid, Oxidation of this product was monitored amperometrically and the current change was then related to ALP activity. Toxicity of herbicides (2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), insecticides (caxbofuran and α-endosulfan) and heavy metals (Hg2+, Cd2+, Ag2+, Zn2+ and Cu2+) towards the biosensor were evaluated. Various degrees of inhibition of ALP occurred when the biosensor was exposed to herbicides and heavy metals. This resulted in a lower acid ascorbic production by the enzyme from the substrate, thus a decrease in the current response of the biosensor. The herbicides 2,4-D and 2,4,5-T showed the largest inhibition effect on ALP with linear response range of 1-60 μg L-1 (R = 0.92). The maximum inhibitions caused by 2,4-D and 2,4,5-T were 46 and 30%, respectively. Heavy metals caused inhibition on ALP at the higher concentration range of mg L-1. Thus, the biosensor may be useful for the screening of chlorophenoxyacetic acid herbicides even in the presence of other environmental toxicants.

AB - An bioelectrochemical sensor or biosensor based on the inhibition of the enzyme Alkaline Phosphatase (ALP) has been investigated for the screening of several environmental toxicants. The biosensor was constructed by immobilizing ALP in a hybrid sol-gel/chitosan film that was deposited on the surface of a screen-printed carbon paste electrode (SPE). The inhibition was measured via the catalytic hydrolysis of ascorbic acid 2-phosphate (AA2P) by the enzyme to produce ascorbic acid, Oxidation of this product was monitored amperometrically and the current change was then related to ALP activity. Toxicity of herbicides (2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), insecticides (caxbofuran and α-endosulfan) and heavy metals (Hg2+, Cd2+, Ag2+, Zn2+ and Cu2+) towards the biosensor were evaluated. Various degrees of inhibition of ALP occurred when the biosensor was exposed to herbicides and heavy metals. This resulted in a lower acid ascorbic production by the enzyme from the substrate, thus a decrease in the current response of the biosensor. The herbicides 2,4-D and 2,4,5-T showed the largest inhibition effect on ALP with linear response range of 1-60 μg L-1 (R = 0.92). The maximum inhibitions caused by 2,4-D and 2,4,5-T were 46 and 30%, respectively. Heavy metals caused inhibition on ALP at the higher concentration range of mg L-1. Thus, the biosensor may be useful for the screening of chlorophenoxyacetic acid herbicides even in the presence of other environmental toxicants.

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KW - Enzyme inhibition

KW - Herbicide

KW - Toxic metal

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