Purification of SDF-1 peptidase activity
Fraction . | Total protein, mg . | Total activity, U . | Specific activity,*AU/min/mg . | Fold purification . |
|---|---|---|---|---|
| Clarified serum | 4771.0 | 2862.6 | 0.6 | 1 |
| 40% ammonium sulphate precipitate | 553.0 | 387.1 | 0.7 | 1.2 |
| Anion exchange† | 32.9 | 700.7 | 21.3 | 35.5 |
| Lysine Sepharose | 0.28 | 29.5 | 105.3 | 175.5 |
Fraction . | Total protein, mg . | Total activity, U . | Specific activity,*AU/min/mg . | Fold purification . |
|---|---|---|---|---|
| Clarified serum | 4771.0 | 2862.6 | 0.6 | 1 |
| 40% ammonium sulphate precipitate | 553.0 | 387.1 | 0.7 | 1.2 |
| Anion exchange† | 32.9 | 700.7 | 21.3 | 35.5 |
| Lysine Sepharose | 0.28 | 29.5 | 105.3 | 175.5 |
An aliquot of protein from each step was tested for SDF-1 peptidase activity in a 10-minute assay. Specific activity was calculated using the area (absorbance units at 205) obtained for the processed peptide per milligram of protein per minute. One unit is equivalent to the generation of 1 AU at 205 nm of cleaved peptide in 1 minute at pH 7.2 at 37°C.
The anion exchange bound material eluted with 0.3 M NaCl. The lysine Sepharose-bound material eluted with 0.15 M NaCl/100 μM SDF-1 peptide.