Abstract
A radioiodinated form of the highly potent enkephalin analog FK 33-824 has been characterized with respect to its binding properties in vitro. 125I-FK 33-824 is distinctive among the short opioid peptides in three ways. First, 125I-FK 33-824 binds stereospecifically to rat brain homogenates with very high affinity (Kd = 0.42 nM). Secondly, dissociation of the 125l-labelled peptide from membrane-bound opiate receptors occurs with a relatively long τ 1 2 of 25 min at 4° in contrast to other enkephalins which dissociate more rapidly. Third, competitive binding analyses reveal that the 125l-FK 33-824 binds equally well to both enkephalin (δ) and morphine (μ) classes of opiate receptors. These characteristics distinguish the 125l-labelled peptide as a particularly suitable probe for molecular studies and purification of the opiate receptor.
Original language | English (US) |
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Pages (from-to) | 99-109 |
Number of pages | 11 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 90 |
Issue number | 1 |
DOIs | |
State | Published - Sep 12 1979 |
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology