title: Studies on modification of tryptophan, methionine, tyrosine and arginine residues of human follicle-stimulating hormone and its subunits.
abstract: Based on the regeneration of the hormonal activity following recombination, the alpha and beta subunits of human follicle-stimulating hormone have been designated as 'functional' or 'nonfunctional'. Chemical modifications of the tryptophan, methionine, tyrosine and arginine residues of human follicle-stimulating hormone, luteinizing hormone, and the 'functional' human follicle-stimulating hormone alpha and beta subunits have indicated that the tryptophan in human follicle-stimulating hormone-beta and human luteinizing hormone-beta is essential for the biological activity. The iodination of human follicle-stimulating hormone-alpha did not interfere with the hormonal activity. The modification of arginine abolishes the biological activity of the hormones. The accessibility of tyrosine and methionine in human follicle-stimulating hormone-alpha, of arginine in both native hormones and subunits, and the non-availability of the tryptophan residues to 2-hydroxy 5-nitrobenzyl bromide suggest that the alpha subunit lies on the surface of the native molecule.
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine; D003488:Cyanogen Bromide; D005640:Follicle Stimulating Hormone; D006037:Glyoxal / Q000031:analogs & derivatives; D007987:Gonadotropin-Releasing Hormone; D006801:Humans; D007454:Iodides; D007461:Iodoacetates; D007986:Luteinizing Hormone; D046911:Macromolecular Substances; D008715:Methionine; D014364:Tryptophan; D014443:Tyrosine
chemical_list: D007454:Iodides; D007461:Iodoacetates; D046911:Macromolecular Substances; D007987:Gonadotropin-Releasing Hormone; D014443:Tyrosine; D006037:Glyoxal; D014364:Tryptophan; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D001120:Arginine; D008715:Methionine; D003488:Cyanogen Bromide