Animal-free Recombinant Human Oncostatin M is expressed in human 293 cells as a monomeric glycoprotein with an apparent molecular mass of 30 kDa. This higher molecular mass is due to glycosylation and is not seen in the E. coli expressed form of this cytokine (22kDa). Glycosylation contributes to stability in cell growth media and other applications. This product is produced in a human cell expression system with serum-free, chemically defined media.