Soil properties influence kinetics of soil acid phosphatase in response to arsenic toxicity
Abstract Soil phosphatase, which plays an important role in phosphorus cycling, is strongly inhibited by Arsenic (As). However, the inhibition mechanism in kinetics is not adequately investigated. In this study, we investigated the kinetic characteristics of soil acid phosphatase (ACP) in 14 soils with varied properties, and also explored how kinetic properties of soil ACP changed with different spiked As concentrations. The results showed that the Michaelis constant ( K m ) and maximum reaction velocity ( V max ) values of soil ACP ranged from 1.18 to 3.77mM and 0.025–0.133mMh −1 in uncontaminated soils. The kinetic parameters of soil ACP in different soils changed differently with As contamination. The K m remained unchanged and V max decreased with increase of As concentration in most acid and neutral soils, indicating a noncompetitive inhibition mechanism. However, in alkaline soils, the K m increased linearly and V max decreased with increase of As concentration, indicating a mixed inhibition mechanism that include competitive and noncompetitive. The competitive inhibition constant ( K ic ) and noncompetitive inhibition constant ( K iu ) varied among soils and ranged from 0.38 to 3.65mM and 0.84–7.43mM respectively. The inhibitory effect of As on soil ACP was mostly affected by soil organic matter and cation exchange capacity. Those factors influenced the combination of As with enzyme, which resulted in a difference of As toxicity to soil ACP. Catalytic efficiency ( V max / K m ) of soil ACP was a sensitive kinetic parameter to assess the ecological risks of soil As contamination. Highlights pH and amorphous Fe explained 50.8–66.1% and 29.8–43.8% of soil ACP V max , K m and V max / K m variations across soils; The type of As inhibition on soil ACP was noncompetitive or mixed inhibition mainly depend on soil types; Soil organic matter and cation exchange capacity were major controlling factors affecting As inhibitory effect on soil ACP. Catalytic efficiency ( V max / K m ) could sensitively indicate the toxicity of As to soil ACP.
유료 다운로드의 경우 해당 사이트의 정책에 따라 신규 회원가입, 로그인, 유료 구매 등이 필요할 수 있습니다. 해당 사이트에서 발생하는 귀하의 모든 정보활동은 NDSL의 서비스 정책과 무관합니다.
원문복사신청을 하시면, 일부 해외 인쇄학술지의 경우 외국학술지지원센터(FRIC)에서
무료 원문복사 서비스를 제공합니다.
NDSL에서는 해당 원문을 복사서비스하고 있습니다. 위의 원문복사신청 또는 장바구니 담기를 통하여 원문복사서비스 이용이 가능합니다.
- 이 논문과 함께 출판된 논문 + 더보기