Urocortin: slower dissociation than corticotropin releasing factor from the CRF binding protein.
We report on a comparison of the kinetics of [125I][Tyr0]corticotropin releasing factor (CRF) and [125I][Tyr0]urocortin binding to the CRF binding protein (CRF-BP) at physiological temperature. The association rates of [125I][Tyr0]urocortin or [125I][Tyr0]CRF binding to the CRF-BP were similar. The half time of association for [125I][Tyr0]urocortin was 3.2 min and for [125I][Tyr0]CRF, 2.6 min. [125I][Tyr0]urocortin dissociated from the CRF-BP but the rate of dissociation was slower than for [125I][Tyr0]CRF. The half time for dissociation of [125I][Tyr0]urocortin was 131 min and for [125I][Tyr0]CRF, 64 min. This slower dissociation indicates that the CRF-BP may be more effective in clearing urocortin than CRF.
Henriot
S
S
Pharma Division, F. Hoffmann-La Roche, Basel, Switzerland.
Dautzenberg
F M
FM
Kilpatrick
G J
GJ
D002352:Carrier Proteins / Q000378:metabolism*; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D006801:Humans; D011485:Protein Binding; D054832:Urocortins
D002352:Carrier Proteins; D054832:Urocortins; C067133:corticotropin releasing factor-binding protein; D003346:Corticotropin-Releasing Hormone