| Abstract: | Methylamine uptake in nitrogen-starved Chlorella pyrenoidosa Beij. follows Michaelis-Menten kinetics: maximum uptake is about 1.6 nmol μl?1· cells · min?1, half-saturation occurs at 4 μM methylamine, and the slope in the range where uptake is proportional to concentration is 0.4 nmol μl?1· min?1·μM?1. In cells grown in the presence of a non-limiting nitrogen concentration, methylamine uptake is directly proportional to concentration up to at least 0.5 mM, and the slope is 1/500 that for starved cells. Similar uptake kinetics have been reported for Penicillium chrysogenum and attributed to an inducible “ammonium permease.” Apparently, a similar permease occurs in algae. |
