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. Author manuscript; available in PMC: 2014 May 29.
Published in final edited form as: Clin Chem. 2013 Oct 21;60(1):233–242. doi: 10.1373/clinchem.2013.211953

Figure 2. Ex vivo peptide cleavage assay on the synthetic C3f peptide.

Figure 2

A. Specific cleavage sites are indicated on the C3f peptide, a substrate of the enzymes factor I, chymotrypsin and CPN. B. Detecting CPN in different assay conditions. CPN-depletion in normal [NIF (CPN -)] or tumor interstitial [TIF (CPN -)] fluid; CPN protein pull-down from normal [CPN (NIF)] or tumor interstitial [CPN (TIF)] fluid. C & D. Normal interstitial fluid (NIF) and tumor interstitial fluid (TIF) (20 μl of 1 mg/ml) from breast cancer mouse model or conditioned medium (CM) of MB-MDA 231 cells were incubated with synthetic C3f peptides (Final concentration is 100 μmol/L) at 37 °C for 1 hour, followed by nanopore fractionation and MALDI-TOF MS. C3f, synthetic peptide His6-C3f_S1304-R1320-His6 only; NIF or TIF, normal or tumor interstitial fluid only; EDTA, an inhibitor of CPN; NIF (CPN -) and TIF (CPN -), CPN-depleted normal and tumor tissue interstitial fluid; CM (CPN -), CPN-depleted conditioned medium.