loss of the intracellular amino acids to the extracellular space accounted for the major portion of their turnover . ( b ) each of the four amino acids noted above appeared to be actively transported into the cell . ( c ) at physiologic extracellular histidine concentrations , histidine entered the cell predominantly by a facilitated process with an apparent michaelis constant of 0.28 mmole/liter and a limiting flux of 14 x 10 ( -8 ) mmumole/min per cell .
C0007613
the cell
C0007634
cell