<unk>  is a part of the<unk> omplex. It binds to actin in thin myofilaments to hold the troponin-tropomyosin complex in place. The letter I is given due to its inhibitory character.
The tissue specific subtypes are:
Slow-twitch skeletal muscle isoform<unk> , TNNI1 (1q31.3, 191042)
Fast-twitch skeletal muscle isoform<unk> , TNNI2 (11p15.5, 191043)
Cardiac<unk> , TNNI3 (19q13.4, 191044)
Troponin I
Troponin T
Creatine kinase
Tropomyosin
Lipase
Myosin
Amylase
Myotilin