• 关键词：碱性磷酸酶  动力学特征  竞争性抑制  天鹅湖

• 基金项目：国家自然科学基金（No.41573120，41103073）

• 吕迎春
• 中国科学院烟台海岸带研究所, 烟台 264003

• 孙志伟
• 1. 中国科学院烟台海岸带研究所, 烟台 264003;2. 鲁东大学, 烟台 264003

• 宋佳伟
• 1. 中国科学院烟台海岸带研究所, 烟台 264003;2. 中国科学院大学, 北京 100049

• 徐刚
• 中国科学院烟台海岸带研究所, 烟台 264003

• 摘要：磷酸酶催化水解有机磷是水体生物有效磷的重要补充途径.以天鹅湖富营养化水体为研究对象，研究了磷和金属对水体中碱性磷酸酶的活性（APA）和动力学性质的影响.结果表明：磷酸根（PO₄^3-）、六偏磷酸根（（PO₃）₆^6-）、焦磷酸根（P₂O₇^4-）、β-甘油磷酸根（（C₃H₄O₆P）^2-）在0.01~1 mmol·L^-1范围内对APA表现为抑制作用，并且抑制作用随浓度的升高而增强：浓度为1 mmol·L^-1时，与对照相比，水体中APA分别降低50.8%、55.8%、52.4%和14.4%.金属Al³⁺、Co²⁺、Pb²⁺和Cr⁶⁺对APA的激活作用随浓度增大而增强，浓度为1 mmol·L^-1时，水体APA分别是空白的2.8、3.1、2.3和2.7倍.重金属Cu²⁺、Zn²⁺、Ni²⁺对水体中碱性磷酸酶表现出抑制作用，3种重金属中Cu²⁺抑制作用最显著.当Cu²⁺浓度为1 mmol·L^-1时，碱性磷酸酶相对活性仅为空白的62.3%.随着Cu²⁺、PO₄^3-、（PO₃）₆^6-、P₂O₇^4-浓度增大，碱性磷酸酶的最大反应速率V_max保持基本稳定，米氏常数K_m增大，因此，它们对碱性磷酸酶的抑制为竞争性抑制类型.同时，V_max/K_m值随Cu²⁺、PO₄^3-、（PO₃）₆^6-、P₂O₇^4-、（C₃H₄O₆P）^2-浓度的增大而降低，催化效率降低，说明V_max/K_m可作为水体磷酸酶催化能力的有效指标.总体而言，含磷基团和金属离子会显著影响富营养化水体APA，将间接影响水体有机磷的转化和供磷效率.

• Abstract：The catalytic hydrolysis of organic phosphorus by phosphatase represents an important source of available phosphorus in surface water. To assess the effects of phosphate and metal ions on alkaline phosphatase activity and kinetic parameters, surface water samples were taken from the coastal Swan Lake water in Rongcheng. Results show that phosphate (PO₄^3-), hexametaphosphates (PO₃)₆^6-, pyrophosphate (P₂O₇^4-) and β-glycerophosphate (C₃H₄O₆P)^2- could inhibit the alkaline phosphatase activity (APA) when their concentrations were in the range of 0.01-1mmol·L^-1. And this inhibition effect increased with the increase of the ion concentrations. In comparison, the APA decreased 50.8%, 55.8%, 52.4% and 14.4% as treated by 1 mmol·L^-1 PO₄^3-, (PO₃)₆^6-, P₂O₇^4-, (C₃H₄O₆P)^2-, respectively. The activation of APA by Al³⁺、Co²⁺、Pb²⁺ and Cr⁶⁺ increased when their concentration increased. After adding 1 mmol·L^-1 Al³⁺, Co²⁺, Pb²⁺ and Cr⁶⁺ to the water, the APA increased by a factor of 2.8, 3.1, 2.3 and 2.7, respectively. The heavy metal Cu²⁺,Zn²⁺,Ni²⁺ were also found to have inhibition effects on APA, especially for Cu²⁺.The residual APA dramatically decreased to 62.3% at 1 mmol·L^-1of Cu²⁺. The significant reduction of an apparent substrate affinity (K_m) and the uniform pattern of maximum APA (V_max) were both observed when the Cu²⁺, PO₄^3-, (PO₃)₆^6-, P₂O₇^4- increased. This phenomenon indicates that Cu²⁺, PO₄^3-, (PO₃)₆^6-, P₂O₇^4- behave in competitive inhibition effects. In addition, V_max/K_m ratio is a good indicator for the catalytic efficiency of alkaline phosphatases in eutrophic water. This research suggests that the phosphate and metal ions can significantly influence APA and has profound implication for the transform and supplement of the organic phosphorus in eutrophic water.

• Key words：alkaline phosphatase  kinetic parameters  competitive mechanism  Swan Lake

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