Table 1.
Comparison of cardiac channel and transporter deduced amino acid sequences
| Current or Transporter | Primary Subunit |
Percentage Amino Acid Sequence Identity |
||||||
|---|---|---|---|---|---|---|---|---|
| Human-Mouse | Human-Guinea Pig | Rat-Mouse | ||||||
| Universally important for mammalian ventricular myocyte function | ||||||||
| INa | SCN5A | 94 | ||||||
| ICa,L | CaV1.2 (CACNA1C) | 94 | ||||||
| IK1 | Kir2.1 (KCNJ2) | 98 | ||||||
| IK1 | Kir2.2 (KCNJ12) | 96 | ||||||
| Ca2+-ATPase | SERCA2 (ATP2A2) | 99 | ||||||
| Na+/Ca2+ exchanger | NCX1 (SLC8A1) | 95 | ||||||
| Functionally important only in larger mammals | ||||||||
| IKs | KCNQ1 | 90 | 91 | |||||
| IKr | KCNH2 | 96 | 96 | |||||
| Functionally important only in small mammals | ||||||||
| Ito,f | Kv4.2 (KCND2) | 99 | 100 | |||||
| IKur | Kv2.1 (KCNB1) | 94 | 97 | |||||
| IKur | Kv1.5 (KCNA5) | 86 | 96 | |||||
INa, sodium channel current; ICa,L, L-type calcium current; IK1, inward rectifier potassium current; IKs, IKr, slow and rapid delayed rectifier potassium currents; Ito,f, transient outward potassium current; IKur, ultrarapid potassium current.