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. Author manuscript; available in PMC: 2015 Dec 1.
Published in final edited form as: J Muscle Res Cell Motil. 2014 Oct 7;35(0):267–278. doi: 10.1007/s10974-014-9390-0

Figure 4. MgATP-sensitivity of myosin cross-bridge detachment rate 2πc at maximal Ca2+ activation (pCa 4.8).

Figure 4

(A) 2πc was elevated as [MgATP] increased from <0.01 to 5 mM in skinned myocardial strips from thyroxin-fed and PTU-fed mice. Solid (controls) and dashed (t/t) lines show fits to Eq. 2. Normalizing 2πc to the asymptotic MgADP release rate (k−ADP; Table 2) demonstrates relative sensitivities to [MgATP] for each population, effectively highlighting (B) the ~2-fold faster MgATP release rate (k+ATP) from α-MyHC for WT t/tT4 vs. t/tT4 and (C) the ~1.5-fold faster k−ADP from β-MyHC for NTGPTU vs. t/tPTU. Insets within panels B and C show data vs. log[MgATP]. †P<0.01; *P<0.05 between experimental and control groups within a panel.