Table 1.

The glucose transport characteristics as determined with different methods at 37°C

	Method	Apparent Vmax, nmol⋅min−1⋅mg⋅protein−1	Apparent Km, mM
Transport	Filtration, 5 seconds	167  ± 11 (n = 6)	1.2  ±  0.2 (n = 6)
	Centrifugation through oil, 5 seconds	151  ±  7 (n = 6)	n.d.
	Centrifugation through oil, 7.5 seconds	91.6*	2.0*
Flux	Steady-state O2-consumption rate	170  ±  6 (n = 15)

For comparison, the maximal steady-state O₂-consumption rate at saturating (50 mM) glucose concentration at 37°C is given. The standard errors of the mean in the filtration experiment and the oxygen consumption experiment are based on n completely independent experiments, with cells isolated from different rats. In each independent replicate of the filtration experiment, the V_max and the K_m were obtained by nonlinear regression from a data-set of at least six points, between 0.1 and 20 mM extracellular glucose, measured in duplicate. Average ± standard error of the mean of n such independent V_max and K_m determinations are given. The V_max of the 5-second centrifugation experiment was measured as the rate of glucose transport at 5.2 mM glucose. Here, n replicates were performed with cells isolated from a single rat. n.d., not determined. 

^*From ref. 14.