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. Author manuscript; available in PMC: 2016 Mar 20.
Published in final edited form as: J Am Chem Soc. 2012 Aug 1;134(32):13259–13265. doi: 10.1021/ja212170b

Figure 3.

Figure 3

Effect of force on collagen heterotrimer proteolysis. (a) MMP-1; (b) Clostridium collagenase. Collagen proteolysis by MMP-1 (a) is fit to the Bell equation, yielding a characteristic distance D = 0.57±0.01 nm. The proteolysis rate measured in bulk solution (blue; see Supporting Information), and closely matches the extrapolated single-molecule rate at zero force. Proteolysis by Clostridium collagenase (b) does not show obvious force dependence, with D ≈ 0 n m. The bulk proteolysis rate (blue) is consistent with rates measured in the single-molecule assay. Clostridium collagenase and MMP-1 concentrations were used such that the proteolysis rates at zero force are roughly comparable.