FIGURE 4.

A, effect of exogenous PKD domain on the digestion of bovine-insoluble type I collagen fiber by the CD of MCP-01. B, the purified recombinant CD. C, the purified recombinant PKD. Insoluble type I collagen fiber (5 mg) was first incubated in the absence and presence of PKD (1 or 5 molar eq) in 50 mm Tris-HCl (with 0.36 mm CaCl₂, pH 7.5) for 5 h at 40 °C, and then equivalents (200 pmol) of MCP-01 (first column) and CD (second column) were added, respectively, and incubated for another 5 h for activity assay. Enzyme activity was determined as mentioned under “Experimental Procedures.” First column, the activity of MCP-01 without PKD treatment; second column, the activity of CD without PKD treatment; third column, the activity of CD with 1 molar eq of PKD treatment; fourth column, the activity of CD with 5 molar eq of PKD treatment.