Purity of recombinant human OSM was determined by SDS- polyacrylamide gel electrophoresis. The protein was resolved in an SDS- polyacrylamide gel in reducing and non-reducing conditions and stained using Coomassie blue.

Recombinant human OSM (HZ-1030) stimulates dose-dependent proliferation of the TF-1 human erythroleukemic indicator cell line. Cell number was quantitatively assessed by PrestoBlue® Cell Viability Reagent. TF-1 cells were treated with increasing concentrations of GMP recombinant OSM for 96 hours. The EC50 was determined using a 4-parameter non-linear regression model. The EC50 range is 0.1-1.5 ng/mL​.