Purification and characterization of a cytostatic factor from the bitter melon Momordica charantia

In this report we describe the purification and characterization of a cytostatic factor from the bitter melon (Momordica charantia). As determined by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), this purified factor is a single component with an apparent molecular weight of 11,000. The factor is not sensitive to boiling or to pretreatments with trypsin, ribonuclease (RNAse), or deoxyribonuclease (DNAse). As determined by radioactive precursor uptake studies, the purified factor preferentially inhibits RNA synthesis in intact tissue culture cells. Some inhibition of protein synthesis and DNA synthesis also occurs. The factor is preferentially cytostatic for IM9 human leukemic lymphocytes when compared to normal human peripheral blood lymphocytes.