The Expression of Human cTnI and cTnC in E.coli and Their Combination Assay

The level of cardiac troponin I is a gold indicator for detecting cardial injury because of its specifity. The genes of cardiac troponin I and C subunits were cloned into pBV220 vector and expressed in E. coli DH5 α respectively. Recombinant proteins of cTnI and cTnC were identified by SDS-PAGE. Two protein bands of 28 ku and 18 ku, were identified as correspondent with the predicted M of cTnI and cTnC, respectively. The recombinant proteins were also confirmed by western blotting using standard cTnI as control. The anti-serum obtained by immunizing Balb/c mice with the purified cTnI can recognize standard cTnI extracted from human heart even diluted more than 16 000 times. At the same time, recombination assay of cTnI and cTnC proteins showed that the two proteins could recognize each other and combine together at the presence of Ca~(2+) and Mg~(2+) as cofactors.