Abstract
In a previous study, we suggested that bovine EPF had a molecular weight of 21.5 KD because a 21.5 KD polypeptide was not found in the nonpregnant serum, and the isoelectric point was near 5.0 by 2D SDS-PAGE using non-equilibrium pH gradient electrophoresis (NEPHGE). We extended the study to characterize the biochemical nature of purified bovine EPF. As a result, the isoelectric point of bovine EPF turned out to be 6.3 by 2D SDS-PAGE using isoelectric focusing (IEF). Also, the purified EPF was not reduced by the addition of 2-mercaptoethanol. Accordingly, it was inferred that bovine EPF is a monomeric peptide. Amino acid analysis of EPF was attempted, but a definitive sequence could not be confirmed. In the present study, the crude anti-EPF lgG fraction was purified by adsorption with CNBr-activated Sepharose 4B coupled with nonpregnant bovine whole serum. The purified anti-EPF IgG decreased the rosette inhibition titer of pregnant serum from 6 to 3. The Sepharose 4B affinity column coupled with anti EPF-IgG effectively isolated the EPF from pregnant bovine serum.
