Fig. 1.

Hog dust extract (HDE) contains proteases that are effectively depleted by protease inhibitor treatment. Undiluted HDE (100% HDE) was treated with various protease inhibitors [2 mM phenylmethylsulfonyl fluoride (PMSF), 4 mM 4-(2-aminoethyl) benzenesulfonyl fluoride-HCl (AEBSF), protease inhibitor cocktail (PIC), or 2 mg/ml porcine trypsin]. Each sample was analyzed by 1% gelatin zymography for the presence of proteolytic activity (indicated at arrows by white clearing/banding; A) or assayed for protease activity by colorimetric azocoll conversion assay (B). Exogenous proteases, porcine pancreatic elastase (PPE, 1 mg/ml), and trypsin (1 mM) were also assayed for comparison. A is representative of 5 or more similar experiments. B depicts means ± SE for 3 independent experiments, with 3 technical replicates per condition. *P < 0.05 vs. 100% HDE. #P < 0.05 vs. HDE + PMSF and HDE + AEBSF. STI, soybean trypsin inhibitor.