COMPARATIVE STUDIES OF LUTEINIZING HORMONE FROM BEEF PORK AND SHEEP PITUITARIES .I. PURIFICATION AND PHYSICAL PROPERTIES

Purification of beef, sheep, and pork luteinlzing hormone (LH) from the pituitary gland is described. The fractionatlon has been selected to give high yield (over 80%) at each step, to obtain material for physical and chemical comparisons. Highly purified preparations have been obtained which are not completely homogeneous, however. The preparations are similar in molecular size (30,000-34,000) as judged by sedimentation-viscosity studies. All show altered sedimentation behavior at low pH, although pork LH behaves differently from sheep and beef LH. Pork LH also has approximately one-half the specific activity of the beef and sheep LH. Peptlde maps of tryptic and chymotryptic digests reveal structural similarities in the preparations although some differences are apparent.