Table 1.

The affinity of individual Na⁺/K⁺-ATPase (NKA) isoforms of FXYD subunits for Na⁺ and K⁺ ions.

Isoform	Affinity for Ions		References
	Na+	K+
1 a	+/−	n.e. b	[62,63]
2	n.e.	+	[64]
3	-	-	[65]
4	+	-	[66]
5	+	-	[67]
6 c	+/−	+/−	[68]
7 c	+/−	n.e.	[69]

^a the affinity for Na⁺ depends on the level of NKA phosphorylation. ^b n.e.—not effective. ^c the affinity for Na⁺ and K⁺ depends also on the α and β isoforms.