Purification of EPF-like substance from bovine ovum culture medium by DISC-preparative electrophoresis.

摘要

Cattle ova were fertilized in vitro and cultured for 72 h in TCM-199 without serum protein. The culture media was then subjected to DISC-preparative electrophoresis. Early pregnancy factor (EPF)-like substance activity was detected in a fraction containing 21.5- and 66-KD protein bands. However, other fractions containing the 66-KD band without the 21.5-KD band were EPF negative so it was concluded that the 21.5-KD band was EPF. No fractions purified from a cumulus cells culture medium had EPF activities or a protein band at 21.5 KD. It is suggested that the EPF-like substance is secreted from the ovum itself.