STRUCTURE OF HUMAN LUTEINIZING-HORMONE BETA SUBUNIT - EVIDENCE FOR A RELATED CARBOXYL-TERMINAL SEQUENCE AMONG CERTAIN PEPTIDE-HORMONES

Amino acid sequence analysis of human luteinizing hormone (lutropin) beta subunit has been carried out in order to reconcile several discrepancies apparent in previously published structures. Our sequence coincides closely with that proposed originally by Shome and Parlow (J.Clin.Endocr.Metab. 36, 618-621, 1973). However, we found a unique solution to the carboxyl-terminal region (-Thr-Cys-Asp-His-Pro-Gln-OH) which is closely homologous with the corresponding segment of hCG and the animal LH beta subunits. The C-terminal three residues appear in closely similar sequences at the C-termini of several other peptide hormones. This suggests a primitive genomic relationship with conservation of this region during evolution of these otherwise divergent polypeptides. © 1979.