Open AccessOn the Role of Tryptophan in Luteinizing‐Hormone‐Releasing Hormone (Luliberin)
Author(s) -
HAZUM Eli,
FRIDKIN Mati,
MEIDAN Rina,
KOCH Yitschak
Publication year - 1977
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1977.tb11806.x
Subject(s) - tryptophan , moiety , indole test , luteinizing hormone , chemistry , hormone , bioassay , biology , biochemistry , stereochemistry , amino acid , ecology
The tryptophan residue of luteinizing‐hormone‐releasing hormone (luliberin) was chemically modified to produce the following analogs: [Trp(o) 3 ]luliberin, Trp ‐(2,4‐dinitrophenylsulfenyl)‐luliberin, Trp ‐(2‐hydroxy‐5‐nitrobenzyl)luliberin, ( Trp ‐S‐luliberin) 2 , Trp ‐CH 3 S‐luliberin and Trp ‐formyl‐luliberin. The luteinizing‐hormone‐releasing activity of these analogs was determined by bioassay in vitro and found to be 0.2%, 0.2%, 0.6%, 1.5%, 1.7% and 7% of that of the natural hormone, respectively. These results demonstrate that alterations in the indole moiety of tryptophan‐3, which lead to a reduction in its electron density or sterically restrict its electron availability, are associated with a dramatic loss of biological activity.