Guanidination of ovine luteinizing hormone and effects on activity.
The free amino groups in oLH, oLHalpha and oLHbeta were guanidinated by O-methylisourea. The epsilon-NH2 groups of lysine residues reacted bo substitute these positions in the sequence with the more basic homoarginine residue. The alpha-NH2 groups did not react under the conditions used. Guanidinated oLH or the products of guanidinated oLHalpha + native oLHbeta or guanidinated oLHalpha + guanidinated oLHbeta were inactive in two bioassay systems. Native oLHalpha + guanidinated oLHbeta, however, showed potencies of 39% to 55% of that observed with the native subunit recombinant or native oLH. Possible structural implications for hormone-receptor site interactions are discussed.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001120:Arginine; D001665:Binding Sites; D001667:Binding, Competitive; D002850:Chromatography, Gel; D006146:Guanidines; D007986:Luteinizing Hormone / Q000378:metabolism; D008239:Lysine; D010902:Pituitary Gland / Q000032:analysis; D011485:Protein Binding; D011956:Receptors, Cell Surface; D012756:Sheep
D000596:Amino Acids; D006146:Guanidines; D011956:Receptors, Cell Surface; D007986:Luteinizing Hormone; D001120:Arginine; D008239:Lysine