Characterization of Recombinant Expressed Tryptases in COS-1 Cells
| . | Secreted Forms . | Intracellular Forms . | ||
|---|---|---|---|---|
| . | Concentration* . | Proteolytic Activity† . | Concentration . | Proteolytic Activity . |
| α-Tryptase | 9 | 8.3 | 11 | 1.0 |
| β-Tryptase | 64 | 39.1 | 38 | <0.001 |
| Mock-transfected | <0.5 | <0.001 | <0.5 | <0.001 |
| . | Secreted Forms . | Intracellular Forms . | ||
|---|---|---|---|---|
| . | Concentration* . | Proteolytic Activity† . | Concentration . | Proteolytic Activity . |
| α-Tryptase | 9 | 8.3 | 11 | 1.0 |
| β-Tryptase | 64 | 39.1 | 38 | <0.001 |
| Mock-transfected | <0.5 | <0.001 | <0.5 | <0.001 |
COS-1 cells were transfected with pcDNAα (α-tryptase), pcDNAβ (β-tryptase), or pcDNA alone (mock-transfected), and supernatants and cell extracts were harvested at 72 hours (48 hours in the presence of 50 μg/mL heparin) as outlined in Materials and Methods. Samples were analyzed for tryptase expression using radioimmunoassay (RIA) and represent the mean from duplicate determinations, expressed in units per liter, standardized to cell number as determined by protein quantification.
Proteolytic activity was determined using the chromogenic substrate TGPA as outlined in the Materials and Methods, and results are expressed in picomolar trypsin equivalents per unit of tryptase.