Evaluation of several strategies for preparing a bovine gonadotropin-like peptide using isotachophoresis, isoelectrofocusing and high-performance liquid chromatography.

Several strategies for preparing a gonadotropin-like, thermostable peptide from the bovine adenohypophysis were compared. Initially, we extracted bovine pituitaries, in the form of an acetone powder, with acetic acid and water. Using one strategy, we isolated the peptide from the crude extract by gel filtration, isotachophoresis, and isoelectrofocusing. The yield was ca. 50 micrograms of peptide from 100 pituitaries. Using another strategy, we isolated the peptide from the crude extract by precipitating the active material with ethanol followed by high-performance liquid chromatography (HPLC). The yield was ca. 500 micrograms of peptide from 100 pituitaries. Using analytical HPLC, we found that material obtained using the different strategies gave similar results. The HPLC route was, however, more efficient and faster than the other routes, and we recommend it for preparing this gonadotropin-like peptide.