Metzger, Jochen and Schnitzbauer, Andreas and Meyer, Manuela and Soeder, Monika and Cuilleron, Claude Y. and Hauptmann, Hagen and Huber, Erasmus and Luppa, Peter B. (2003) Binding analysis of 1 alpha- and 17 alpha-dihydrotestosterone derivatives to homodimeric sex hormone-binding globulin. BIOCHEMISTRY, 42 (46). pp. 13735-13745. ISSN 0006-2960
Full text not available from this repository. (Request a copy)Abstract
Binding studies of the interaction of immobilized 1alpha- and 17alpha-aminoalkyl derivatives of 5alpha-dihydrotestosterone (DHT) with purified N-deglycosylated homodimeric human sex hormone-binding globulin (SHBG) were performed using a surface plasmon resonance biosensor. These 1alpha- and 17alpha-derivatives with spacers of appropriate lengths between the amine function and the steroid ring skeleton enabled privileged, sterically undisturbed, interactions of either the 17- or 3-characteristic functional groups of DHT with SHBG. The association constants (K(a)1) for the binding of these immobilized DHT derivatives to the first binding site of SHBG, determined by SPR measurements, were 0.16 x 10(7) M-1 for 17alpha-aminopropyl-17beta-hydroxy-5alpha-androstan-3-one (1), 1.64 x 10(7) M-1 for 17alpha-aminocaproyl-17beta-hydroxy-5alpha-androstan-3-one (2), and 1.2 x 10(8) M-1 for 1alpha-aminohexyl-17beta-hydroxy-5alpha-androstan-3-one (3). These values were compared with global K-a data for the corresponding nonimmobilized DHT derivatives from equilibrium measurements using competitions with a tritiated testosterone tracer: the K-a values were 1.25 x 10(7) M-1 for 1, 1.50 x 10(7) M-1 for 2, and 140 x 10(7) M-1 for 3, confirming a remarkably high binding affinity of this latter compound for SHBG. A global fitting analysis of the biosensor data revealed that the interaction of the three immobilized steroids with SHBG was best described by a kinetic model assuming two structurally independent binding sites. This hypothesis of a bivalent binding model was also directly suggested by a dual fluorescent signal observed by the flow cytometry analysis of SHBG immobilized as a hybrid complex binding simultaneously two 1alpha-aminohexyl DHT ligands, one formed by 3, covalently coupled to phycoerythrin-labeled latex microspheres, and the other by the same DHT derivative, coupled to a fluorescein derivative (4).
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | METABOLIC-CLEARANCE RATE; ANTIBODY-ANTIGEN INTERACTIONS; HUMAN-BLOOD-PLASMA; STEROID-BINDING; ANDROGEN-BINDING; DIMERIZATION DOMAINS; KINETIC-ANALYSIS; PROTEIN SBP; LIGAND-BINDING; TESTOSTERONE; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Organische Chemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 27 Jul 2021 10:57 |
| Last Modified: | 27 Jul 2021 10:57 |
| URI: | https://pred.uni-regensburg.de/id/eprint/38397 |
Actions (login required)
 |
View Item |
