Figure 3.

The specific affinity of recombinant rat β-defensin 22 for heparin beads. Recombinant β-defensin 22 (100 µg) bound on heparin beads (100 µl) was eluted with elution buffer containing varying concentrations of NaCl and analysed on a 15% SDS–PAGE gel (a). Arrow indicates the band of recombinant protein eluted with minimal NaCl concentration. The purified rat β-defensin 22 with addition of either free heparin (b) or free chondroitin sulphate (c) was incubated with heparin beads. The unbound protein and the eluate of the heparin beads (bound) were analysed on 15% SDS–PAGE. ‘+' represents the addition of equal amount of rat β-defensin 22 to the incubation system at a working concentration of 0.8 mg ml⁻¹. ‘−' indicates the addition of an equal volume of binding buffer. SDS–PAGE, sodium dodecyl sulphate–polyacrylamide gel electrophoresis.