Granulocyte macrophage colony-stimulating factor (GM-CSF) controls the production, differentiation, and function of granulocytes and macrophages. The active form of the protein is a homodimer. GM-CSF stimulates the growth and differentiation of hematopoietic precursor cells from various lineages, including granulocytes, macrophages, eosinophils, and erythrocytes.
This protein is produced in yeast as a single glycosylated peptide chain of 127 amino acids with a molecular weight of 26-32 kDa. Recombinant GM-CSF differs from native human GM-CSF by an arginine to leucine substitution at amino acid 23. The carbohydrate moiety of the recombinant form may be different than that of the native protein. rGM-CSF is purified by proprietary chromatographic techniques. The first five amino acids have been sequenced and found to be APARS.
The protein was lyophilized from a 1 mg/ml solution containing 10 mM phosphate buffer pH 7.0 containing mannitol and sucrose as stabilizers. The purity is greater than 97% as determined by reverse-phase HPLC and SDS-PAGE. The ED50 is determined by stimulation of human TF-1 cells and is less than 0.183 ng/ml, corresponding to a specific activity of 5,500,000 IU/mg.