Figure 4. Cellular distribution and enzymatic activity of zebrafish CPA6.

(A) EGFP-tagged CPA6 (+) or EGFP only (−) were expressed in HEK293T cells. Media, cell and ECM extracts were resolved by SDS-PAGE and western blotted with an anti-GFP antibody, showing the majority of processed CPA6-EGFP (asterisk) localized to the ECM. (B) ECM from cells transfected with zCPA6 was incubated with fa-FF at the pH values indicated or (C) with a range of commercially available fa substrates at pH 7.5. CP activity was determined by a change in substrate absorbance at 336 nm. Error bars indicate range of duplicate determinations from a representative experiment. Similar results were obtained in two separate experiments.