Biomaterial Database

Affinity labelling of human transcortin. 1977

F Le Gaillard, and M Dautrevaux

The binding site of transcortin has been studied by using bromoacetyltestosterone and bromoacetylated derivatives of progesterone which were monohydroxylated at different positions of the steroid nucleus. Specificity of affinity labelling was demonstrated by the displad cortisol analog was added to a [3H]cortisol-transcortin complex solution. The binding site crevice was found to be very narrow in the vicinity of the A and B rings of steroid since 2alpha-hydroxyprogesterone, 6alpha- or 6beta-bromoacetoxyprogesterone and dexamethasone could not displace bound cortisol. A specific affinity labelling was obtained with 11alpha-bromoacetoxyprogesterone, 16alpha-bromoacetoxyprogesterone and 17beta-bromoacetyltestosterone. The results of the affinity labelling by these hormone analogs suggested that one methionine and one histidine residues were located within the active site:methionine might interact with the 11beta-hydroxyl group and histidine with the 20 keto group of cortisol.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008968	Molecular Conformation	The characteristic three-dimensional shape of a molecule.	Molecular Configuration,3D Molecular Structure,Configuration, Molecular,Molecular Structure, Three Dimensional,Three Dimensional Molecular Structure,3D Molecular Structures,Configurations, Molecular,Conformation, Molecular,Conformations, Molecular,Molecular Configurations,Molecular Conformations,Molecular Structure, 3D,Molecular Structures, 3D,Structure, 3D Molecular,Structures, 3D Molecular
D011374	Progesterone	The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION; PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS.	Pregnenedione,Progesterone, (13 alpha,17 alpha)-(+-)-Isomer,Progesterone, (17 alpha)-Isomer,Progesterone, (9 beta,10 alpha)-Isomer
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006854	Hydrocortisone	The main glucocorticoid secreted by the ADRENAL CORTEX. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions.	Cortef,Cortisol,Pregn-4-ene-3,20-dione, 11,17,21-trihydroxy-, (11beta)-,11-Epicortisol,Cortifair,Cortril,Epicortisol,Hydrocortisone, (11 alpha)-Isomer,Hydrocortisone, (9 beta,10 alpha,11 alpha)-Isomer,11 Epicortisol
D006908	Hydroxyprogesterones	Metabolites or derivatives of PROGESTERONE with hydroxyl group substitution at various sites.
D000345	Affinity Labels	Analogs of those substrates or compounds which bind naturally at the active sites of proteins, enzymes, antibodies, steroids, or physiological receptors. These analogs form a stable covalent bond at the binding site, thereby acting as inhibitors of the proteins or steroids.	Affinity Labeling Reagents,Labeling Reagents, Affinity,Labels, Affinity,Reagents, Affinity Labeling
D000596	Amino Acids	Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.	Amino Acid,Acid, Amino,Acids, Amino
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D001667	Binding, Competitive	The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.	Competitive Binding