L-alanine uptake by frog (Rana esculenta) red blood cells

L-Alanine uptake has been studied in frog red blood cells. The present study shows the presence of different carriers for this amino acid in these cells. In the physiological concentration range, most L-alanine is taken up through the Na(+)-dependent system ASC, although the sodium-independent systems asc and L are also active. The competitive inhibition data obtained makes difficult to differentiate the two Na(+)-independent activities in a clear contrast with data from fish or mammalian erythrocytes, indicating that despite its widespread occurrence in vertebrates, these carriers show characteristics that are species specific.