Table 1. Mutuations in the heparin-binding motif of recombinant human diamine oxidase (rhDAO) reduce binding to heparin-sepharose.
| rhDAO | NaCl | KCl | Mean (SD) | ||
|---|---|---|---|---|---|
| Concentration (mM) | Reduction (mM) | Concentration (mM) | Reduction (mM) | Reduction (mM) | |
| WT | 372 | 0 | 310 | 0 | 0 (na) |
| R568S | 186 | 186 | 172 | 138 | 162 (24) |
| K575T | 317 | 55 | 233 | 77 | 66 (11) |
| R568S/R571T | 175 | 197 | 138 | 172 | 185 (13) |
| R568S/K575T | 197 | 175 | 164 | 146 | 161 (15) |
| K570G/R571Q/K572T* | 219 | 153 | - | - | - |
Purified rhDAO-WT and various HBM mutants were loaded onto a heparin-sepharose column and eluted with linear gradients of 0–1 M NaCl or KCl. The salt concentrations necessary for rhDAO elution and the reduction thereof compared to the wildtype protein are shown. The physiological salt concentration in blood plasma and interstitial fluid is approximately 145 mM.
*
Corresponds to the HBM in guinea pig, dog, rat, mouse, and Chinese hamster.
HBM = heparin-binding motif; SD = standard deviation; na = not applicable.