Structural Aspects of Luteinizing Hormone Actions

This chapter reviews the structural aspects of luteinizing hormone (LH) with an emphasis on the effects of structural modification on hormone action. It considers the activity of the subunits of luteinizing hormone, their activity after recombination, and the effects of chemical cross-linking on activity. The chapter also reviews the functional group reaction studies for the protein portion of the molecule, considering either specific functional groups or the effects of a class of reactions on several or all of a given type of functional group. The low biological activity sometimes ascribed to subunit preparations has been attributed to contamination with low amounts of intact hormone or to contamination with small quantities of the complementary subunit which, under suitable conditions, becomes reassociated. Modification of 8 to 10 arginine groups in LH reduces the biological activity of the modified hormone to about 15% of that for the native hormone.