Methods of producing improved bone morphogenetic proteins

A method for producing BMP-2 comprising the steps of: i) culturing a suitable host cell comprising a DNA molecule encoding a BMP-2 in a culture medium comprising iron at a concentration of at least 2.25 uM, a polyanionic compound, and if pyridoxal is present, represents less than 55% of the molar concentration of vitamin B6 in the culture medium; and ii) recovering the protein of interest, wherein the host cell is cultured in a bioreactor having a capacity of at least 160 l, wherein the culture medium further comprises copper at a concentration of at least 10 nM; and wherein the suitable host cell is a CHO cell.