Abstract
An acidic extract of egg white stimulated the DNA synthesis and proliferation of BALB/c 3T3 cells. The maximal degree of DNA synthesis in 3T3 cells in the presence of the egg white extract was half that in the presence of 10% calf serum. However, such activity was not detected in an egg yolk extract. The activity of the egg white extract was divided between two fractions of about 7 kD and 2 kD, both of them were stable in 6 M urea, from pH 2 to 12 and at high temperature. The former was inactivated by treating with 2-mercaptoethanol. The activity of both fractions is attributed to polypeptide compounds, because the activity of each was lost by pronase digestion.
