Purification and characterization of the biologically active human truncated macrophage colony-stimulating factor expressed in Saccharomyces cerevisiae.

: A human truncated macrophage colony-stimulating factor (M-CSF) cDNA encoding amino acid residues from 3 to 149 of the native M-CSF was isolated by using the polymerase chain reaction. When introduced into Saccharomyces cerevisiae by a general secretion vector pVT 102u/alpha, it directs the expression of the biologically active dimeric form of M-CSF. Through the 3 stages of purification, i.e. concentration by DEAE-cellulose column chromatography, hydrophobic chromatography on phenyl-sepharose and Mono Q fast protein liquid chromatography, the recombinant truncated M-CSF was purified as to exhibit a specific activity of 1.02 x 10(7) units/mg of protein. SDS-PAGE of this purified truncated M-CSF showed that its apparent molecular mass is 22 kDa under reducing conditions.