Preliminary studies on the significance of alkaline phosphatase activity in the diatom Phaeodactylum tricornutum Bohlin
Year: 1997
Type: article
Abstract: Alkaline phosphatase activity (APA) and total cellular phosphorus were investigated in batch culture of the diatom Phaeodactylum tricornutun Bohlin. The alga used three phosphomonoesters as P source: p-nitrophenylphosphate (pNPP), methyl-umbelliferylphophate (MUP) and s-glycerophosphate. The enzyme exhibited an apparent negative cooper- ativity for the hydrolysis of pNPP and MUP. Affinity was higher for MUP than for pNPP, but maximum velocity was sim- ilar. Incubation at phosphate concentration < 50 ∝M shows no effect on APA, but the enzymatic activity decreased marked- ly at higher phosphate concentrations. The decrease depended on the time of incubation (4 days), suggesting repression of enzyme synthesis. In cultures supplied with s-glycerophosphate the enzyme utilised preferentially this substrate, instead of MUP. Phosphatase activity was inversely related with total phosphorus content. The ability to take up phosphate and APA increased markedly with increased phosphorus deficiency. Maximum APA (27 fg MU cell -1 h -1 ) was observed when phos- phate uptake was high (V max =6.5 fm P cell-1 h-1) and phosphorus content was low (0.33 pg P cell-1). In contrast, a minimum APA (1.4 fg MU cell -1 h -1 ) was associated to low phosphate uptake (less than 1 fm P cell -1 h
Source: Scientia Marina
Authors: Roberto García‐Ruiz, Francisco Xavier Niell Castanera, Ignacio Hernández, Juan J. Lucena
Language: English
Topic: Diatoms and Algae Research
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W128926398