Hall MA et al. (2010), m-Azipropofol (AziPm) a photoactive analogue of...

XB-ART-42051

J Med Chem 2010 Aug 12;5315:5667-75. doi: 10.1021/jm1004072.

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m-Azipropofol (AziPm) a photoactive analogue of the intravenous general anesthetic propofol.

Hall MA , Xi J , Lor C , Dai S , Pearce R , Dailey WP , Eckenhoff RG .

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Propofol is the most commonly used sedative-hypnotic drug for noxious procedures, yet the molecular targets underlying either its beneficial or toxic effects remain uncertain. In order to determine targets and thereby mechanisms of propofol, we have synthesized a photoactivateable analogue by substituting an alkyldiazirinyl moiety for one of the isopropyl arms but in the meta position. m-Azipropofol retains the physical, biochemical, GABA(A) receptor modulatory, and in vivo activity of propofol and photoadducts to amino acid residues in known propofol binding sites in natural proteins. Using either mass spectrometry or radiolabeling, this reagent may be used to reveal sites and targets that underlie the mechanism of both the desirable and undesirable actions of this important clinical compound.

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Species referenced: Xenopus laevis
Genes referenced: gabarap kidins220 mrpl24

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References [+] :

Akk, Activation and block of recombinant GABA(A) receptors by pentobarbitone: a single-channel study. 2000, Pubmed

	Scheme 1.
	Figure 1. Isothermal titration calorimetry of the HSAF interaction with either 1 (left) or propofol (right), using sequential titrations. More sigmoid shaped curve with propofol indicates higher affinity, consistent with the values given in Table 2.
	Figure 2. Fluorescence competition with 1-aminoanthracene. Titration of the HSAF/1-AMA combination with either 1 (filled symbols) or propofol (open symbols) produced inhibition of fluorescence consistent with competition for binding. Lines represent nonlinear least-squares fits to variable slope Hill functions. Values are given in Table 2.
	Figure 3. Photo-occlusion experiment. In order to confirm that fluorescence competition was not due to inner filter or other nonspecific interactions between 1-AMA, 1, and HSAF, the protein was photoadducted by 1/UV, washed, and then evaluated for 1-AMA binding via fluorescence enhancement. The photoadducted sample had significantly reduced 1-AMA binding compared to the UV control, consistent with adduction in the 1-AMA anesthetic binding site.
	Figure 4. In vivo dose/response relationships. Tadpoles were evaluated with two end points: spontaneous (left set of curves, squares) and elicited (right set of curves, circles) movement. Filled symbols represent 1, and open symbols are propofol data. No significant differences between the two drugs could be detected for either end point.
	Figure 5. Electrophysiology in GABAA receptors. Excised patches containing Î±1Î²2Î³2L receptors were exposed to 3 Î¼M GABA alone (left column) or together with propofol (middle column) or 1 (right column) for 500 ms. At 0.3 and 3 Î¼M, both compounds enhanced responses to GABA. At a high concentration (30 Î¼M), propofol directly activated channels, whereas 1 blocked channels.
	Figure 6. Adducted HSAF residues. Shown is the HSAF anesthetic binding site with propofol bound (yellow), from PDB code 3F33. Residues photolabeled by 1 (L24 and L81 from each of two monomers) (pink) are immediately adjacent to propofol. Mass spectra are provided in the Supporting Information.