Kinetics of glucose transport in K-562 cells was studied using 3-O-methylglucose, a nonmetabolizable analog of glucose. A Km of 3.7 mM and Vmax of 32.0 nmoles/minute/10(6) cells was found for the process. D-Glucose, phloretin, and phlorizin competitively inhibit the transport of 3-O-methylglucose with Ki values of 4.1 mM, 4.1 muM and 225 muM, respectively, whereas L-glucose did not inhibit transport at all. The results indicate that K-562 cells, which are known to have erythropoietic characteristics, possess a glucose carrier system similar to the one in adult human erythrocytes. However, the Vmax data suggest that more copies of the carrier are present in the malignant cell, presumably to support the high rate of anaerobic glycolysis.