Jr. Perezcastineira et al., KINETIC-PROPERTIES OF SULFATE UPTAKE IN 2 TYPES OF EUKARYOTIC GREEN MICROALGAE, Journal of plant physiology, 153(3-4), 1998, pp. 324-331
Sulfate uptake in two different green algae, Chlamydomonas reinhardtii
strain 21 gr and Monoraphidium braunii strain 202-7d was studied by m
easuring the radioactivity accumulated inside the cells when incubated
in the presence of S-35-labelled sulfate. In both cases, uptake is a
light-dependent saturable process that showed maximal rate at 300 mu m
ol/L sulfate for C, reinhardtii and 50 mu mol/L for M. braunii. Experi
mental data were analysed both graphically and by computer fitting to
different kinetic models. Whereas two Km values of around 1 and 50 mu
mol/L could be observed in C, reinhardtii, M. braunii showed a typical
Michaelis behaviour, with one Km value of around 5 mu mol/L. Studies
performed with C, reinhardtii cells in the presence of different inhib
itors strongly support multiphasic kinetics for sulfate uptake in this
alga.