TABLE 1.

Quantification of human and rat α1 in H1299 cells

Intensities of the 140- and 110-kDa α1 bands in Fig. 7A were first translated to absolute amounts of α1 protein (in ng/mg of protein of whole cell lysate) by means of the calibration curve of Fig. 7B. Contributions of rat and human α1proteins to the 110-kDa band of transfected cells were then calculated assuming that the ratio of YFP-α1 to untagged human α1 is the same for the nontransfected and rat α1-transfected cells.

Na+/K+-ATPase isoform	α1 protein
	Nontransfected cells	Rat α1-transfected cells
	ng/mg cell protein
Human YFP-α1	64.3	56.6
YFPα1 + untagged human α1	243.1	198.9
Rat α1		131.0
Rat/human α1 ratio		0.66