Metabolism of [14C]bicarbonate byStreptococcus lactis: the synthesis, uptake and excretion of aspartate by resting cells

Abstract

SummaryResting cells ofStreptococcus lactisC10 were able to synthesize aspartic acidde novobut could not actively transport aspartic acid into the cell. Intracellular aspartate was excreted from the cell in the presence of glucose but did not exchange with any extracellular amino acids. The results indicated thatStr. lactisC10 obtains the aspartic acid it requires for growth by bicarbonate fixation instead of by the utilization of extracellular aspartic acid.