Affinity Labeling of Hormone-Specific Proteins

AFFINITY labeling for studying the amino acid topography of specific binding sites in biologically important proteins has emerged as an important biochemical technique during the past three decades. Hormone-specific proteins have been the subjects of affinity labeling during the past two decades, beginning with the analysis of the amino acids which constitute the catalytically active site of the enzymes involved in steroid biosynthesis. More recently, hormone-specific receptor and transport proteins have been characterized, and the amino acid compositions of their binding sites have been described by affinity labeling. The reagents used for affinity labeling are analogs of hormones which produce active site-directed irreversible inhibition in the proteins which they attack. Therefore, they have been regarded as potential new drugs for controlling fertility, treating endocrine disorders, and for treating hormone-sensitive cancers. The three major categories of affinity labeling hormone analogs have been cl...