Troponin I （TnI）， troponin T （TnT） and troponin C （TnC） form the troponin complex of the thin filaments of striated muscle. TnI is acts as the inhibitory subunit by blocking actin-myosin interactions and thereby mediating striated muscle relaxation. The TnI subfamily contains 3 genes: TnI-skeletal-fast-twitch， TnI-skeletal-slow-twitch， and TnI-cardiac. The TNNI3 gene encodes the TnI-cardiac protein and is exclusively expressed in cardiac muscle tissues. Mutations in the TNNI3 gene cause familial hypertrophic cardiomyopathy type 7 （CMH7） and familial restrictive cardiomyopathy （RCM）.
TNI although stable at room temperature for 3 weeks， should be stored desiccated below -18℃. Upon reconstitution TNI should be stored at 4℃ between 2-7 days and for future use below -18℃. For long term storage it is recommended to add a carrier protein （0.1% HSA or BSA）. Please prevent freeze-thaw cycles.
