FIGURE 2.

Effect of myofibril species on the rate of Ca²⁺ dissociation from Tn-exchanged rigor myofibrils. TnC_IANBD^T53C Tn was exchanged into rat, dog, and failing human ventricular myofibrils to acquire the apparent rates of Ca²⁺ dissociation for the respective myofibrils. The rigor Ca²⁺ dissociation rates for the different species were; rat (16.7 ± 0.5/s), dog (21.6 ± 0.7/s), and failing human ventricular myofibrils (22.9 ± 0.9/s). Buffer conditions were identical to those described for panel B of Fig. 1. All traces were acquired at 15 °C. The data traces were normalized and staggered for clarity.