"RIV/60077387:_____/01:62013084!RIV/2003/AV0/A62003/N" . "Kop\u00E1\u010Dek, Ji\u0159\u00ED" . . . "P(GA206/00/0063), P(GA206/97/0072), Z(AV0Z6017912)" . . . "GB - Spojen\u00E9 kr\u00E1lovstv\u00ED Velk\u00E9 Brit\u00E1nie a Severn\u00EDho Irska" . . . "[CF4DE69EEB10]" . . "Environmental Microbiology" . . . . "Impact of ionic aluminium on extracellular phosphatases in acidified lakes."@en . . . "10"^^ . "Bittl, T." . "Direct inhibiting effects of Al on extracellular phosphatases produced by the plankton were studied in lab experiments. Significant reduction of an apparent substrate affinity was found at Al concentrations 300-1000 g l^-1 at pH 4.5 and 4.8, while maximum acid phosphatase activity (APA) remained unchanged. Such behaviour of saturation kinetics is compatible with the assumption that ionic Al acts as a competitive inhibitor. To decide whether the observed Al effects could be explained alternatively by complexation of Al with substrate, the best fits of data with both possible models was statistically tested. Experimental results supported the competitive hypothesis rather than the complexation model. For pH values <5.2, the results of an Al-pH matrix experiment gave a more detailed picture: the higher the Al concentration, the wider was the pH range where Al could negatively affect APA. The ecological ramifications of this effect were evaluated in the context of field APA data on three strong" . "Vrba, Jaroslav" . "1462-2912" . . . "682452" . . "3" . "Impact of ionic aluminium on extracellular phosphatases in acidified lakes." . "578;587" . . . . "Impact of ionic aluminium on extracellular phosphatases in acidified lakes."@en . "4"^^ . "0"^^ . "RIV/60077387:_____/01:62013084" . . "Direct inhibiting effects of Al on extracellular phosphatases produced by the plankton were studied in lab experiments. Significant reduction of an apparent substrate affinity was found at Al concentrations 300-1000 g l^-1 at pH 4.5 and 4.8, while maximum acid phosphatase activity (APA) remained unchanged. Such behaviour of saturation kinetics is compatible with the assumption that ionic Al acts as a competitive inhibitor. To decide whether the observed Al effects could be explained alternatively by complexation of Al with substrate, the best fits of data with both possible models was statistically tested. Experimental results supported the competitive hypothesis rather than the complexation model. For pH values <5.2, the results of an Al-pH matrix experiment gave a more detailed picture: the higher the Al concentration, the wider was the pH range where Al could negatively affect APA. The ecological ramifications of this effect were evaluated in the context of field APA data on three strong"@en . "9" . . "0"^^ . "3"^^ . "acid phosphatases; pH effect; inhibition"@en . "Nedoma, Ji\u0159\u00ED" . "Impact of ionic aluminium on extracellular phosphatases in acidified lakes." .