A quenched-flow technique for the measurement of glucose influx into human red blood cells.

A quenched-flow apparatus is described and applied to measurements of the hydrolysis of 2,4-dinitrophenyl acetate by sodium hydroxide and the entry of D-[U-14C]glucose into human red blood cells at 37 degrees C. Glucose influx into red cells was a saturable process obeying Michaelis-Menten kinetics with a Km for glucose of 6.6 +/- 0.61 mM and a maximum rate for glucose entry under "zero trans" conditions of 20.7 +/- 0.76 mmol (L cell water)-1 s-1. The technique used requires only readily available laboratory equipment and should be easily adaptable to the study of other rapid transport processes.