- Title
- Respecting catalytic efficiency of soil arylsulfatase as soil Sb contamination bio-indicator by enzyme kinetic strategy
- Creator
- Ma, Xing; Tian, Haixia; Dai, Yunchao; Yang, Yizhe; Megharaj, Mallavarapu; He, Wenxiang
- Relation
- Environmental Science and Pollution Research Vol. 30, Issue 7, p. 17644-17656
- Publisher Link
- http://dx.doi.org/10.1007/s11356-022-23338-5
- Publisher
- Springer
- Resource Type
- journal article
- Date
- 2022
- Description
- Antimony (Sb), a toxic metalloid, is ubiquitous in the environment and threatens human and ecological health. Soil arylsulfatase (ARS) activity indicates heavy metal pollution. However, the enzyme’s substrate concentration can affect the toxicity evaluation of heavy metals using enzyme activity. Enzyme kinetic parameters directly reflect the potency of heavy metals, and the magnitude of these parameters does not change with the substrate concentration of soil enzyme. In this work, seventeen soils were exposed to Sb contamination to investigate the change of kinetic parameters of soil arylsulfatase under Sb stress. Results showed that Sb inhibited soil arylsulfatase activity. The maximum reaction rate (Vmax) of soil arylsulfatase was reduced by 11.58–46.72% in 16 tested soils and unchanged in S15 when exposed to Sb. The Michaelis constant (Km) presented three trends: unchanged, increased by 28.46–41.27%, and decreased by 19.71–29.91% under Sb stress. The catalytic efficiency (Ka as the ratio of Vmax to Km) decreased by 12.56–55.17% in all soils except for S12 and S16. Antimony acted as a non-competitive and linear mixed inhibitor by decreasing ARS activity in S1–S12, S14, and S17–S18 soils, as an uncompetitive inhibitor in S13 and S16 soils and as a competitive inhibitor in S15. The competitive and uncompetitive inhibition constants (Kic and Kiu) were 0.058–0.142 mM and 0.075–0.503 mM. The ecological dose values of Sb to catalytic efficiency (Ka) of ARS (ED10-Ka) ranged from 50 to 1315 mg kg−1. Soil pH and total phosphorus (TP) contents were the dominant factors responsible for Sb toxicity on Ka by affecting the interaction of inhibitor (Sb) with enzyme-substrate (ES) complex. The findings of this study advance the current knowledge on Sb toxicity to soil enzymes and have significant implications for the risk assessment of Sb in soils.
- Subject
- antimony; soil arylsulfatase; enzyme kinetics; catalytic efficiency; ecological dose; SDG 3; Sustainable Development Goals
- Identifier
- http://hdl.handle.net/1959.13/1489824
- Identifier
- uon:52779
- Identifier
- ISSN:0944-1344
- Language
- eng
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