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Chemical Compound Review

FT-0662050     1H-pyridin-6-amine

Synonyms: AC1L9FZ1, 2AP, pyridin-1-ium-2-amine
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Disease relevance of Aminopyridine


High impact information on Aminopyridine

  • A structure in which dA:dT Watson-Crick base pairs alternate with Hoogsteen syndG:dCH+ pairs appears to be the most stereochemically acceptable structure consistent with the chemical properties of this protonated DNA [6].
  • A protonated form of a cloned simple repeating DNA sequence d(TC)n X d(GA) is detectable in equilibrium with the usual Watson-Crick base-paired form at pHs up to 7 [6].
  • Its seven transmembrane helices encompass a proton translocation pathway containing the chromophore, a retinal molecule covalently bound to lysine 216 through a protonated Schiff base, and a series of proton donors and acceptors [7].
  • The lifetime of the protonated state correlates with the occupancy of an intra-channel binding site by the permeant cation [8].
  • Hydrogen ions gain access to this region of the sodium channel (and hence determine the relative local concentration of protonated drug) more readily from the extracellular fluid than from the axoplasm (Schwarz et al 1977) [9].

Chemical compound and disease context of Aminopyridine


Biological context of Aminopyridine


Anatomical context of Aminopyridine

  • This S163R mutation provides insight into a mechanism by which PfCRT could gate the transport of protonated chloroquine through the digestive vacuole membrane [20].
  • Previous in vitro experiments suggest that protonated 2,4,6-triaminopyrimidine (TAP+) inhibits passive Na+ movement across tight junctions of various epithelial tissues [21].
  • CONCLUSIONS: Uptake of glycine- or taurine-conjugated bile acids by the guinea pig jejunum occurs by at least two mechanisms: carrier-mediated transport (dihydroxy conjugates greater than trihydroxy conjugates) and passive absorption in protonated (uncharged) form of glycine conjugates [22].
  • With few exceptions, weakly basic compounds that are sufficiently lipophilic in their neutral forms and sufficiently hydrophilic in their protonated forms accumulate in lysosomes [23].
  • Fourier difference maps were calculated from the differences in inplane diffraction from the deuterated membranes and from protonated samples that were prepared in exactly the same way [24].

Associations of Aminopyridine with other chemical compounds

  • Here we report that binding of permeant cations to an intra-channel binding site of the dihydropyridine (DHP)-sensitive (L-type) Ca2+ channel leads to a conformational change which destabilizes the protonated state of a group on the external channel surface, and can shift its apparent pK value by more than 2 pH units [8].
  • Rhodopsin is composed of two parts: a polypeptide chain called opsin and an 11-cis-retinal chromophore covalently bound to the protein by means of a protonated Schiff base linkage to Lys296 located in the seventh transmembrane segment of the protein [25].
  • When intraluminal pH was decreased to pH 5.0, the absorption rate of glycine (but not taurine) conjugates increased, indicating passive absorption of the protonated species of glycine-conjugated bile acids [22].
  • In native apomyoglobin, His-24 cannot be protonated, although at pH 4 the native protein forms a molten globule folding intermediate in which the histidine residues are readily protonated [26].
  • In contrast, the pairing of protonated cytosine is consistent with the greater stability of oligonucleotide duplexes containing cytosine.O6-MeGua as compared with thymine.O6-MeGua base pairs [Gaffney, B. L., Markey, L. A. & Jones, R. A. (1984) Biochemistry 23, 5686-5691] [27].

Gene context of Aminopyridine

  • Rhodopsin bears 11-cis-retinal covalently bound by a protonated Schiff base linkage [28].
  • We have hypothesized that the anionic fatty acid head group is translocated by UCP, and the proton is transported electroneutrally in the bilayer by flip-flop of the protonated fatty acid [29].
  • We conclude that the binding site of Drosophila rhodopsin is similar to that of bovine rhodopsin and is characterized by a protonated Schiff base chromophore stabilized via a single negatively charged counterion [30].
  • Together, these results suggest that histidine 295 is not protonated in EAAC1 at physiological pH and, thus, does not contribute to H(+) cotransport [31].
  • We found that the compounds with a nitro group on the benzyl ring were poor substrates for P-gp despite the presence of a secondary amine that can be protonated [32].

Analytical, diagnostic and therapeutic context of Aminopyridine

  • Analysis of the theoretical microscopic titration curves for all of the ionizable residues of these proteins shows that a small fraction (3-7%) of the curves possess a flat region where the residue is partially protonated over a wide pH range [33].
  • FTIR difference spectral changes in the bR570-to-K transition clearly indicate that bR570 contains a protonated Schiff base [34].
  • Resonance Raman spectroscopy provides evidence that bR570 is protonated, but these results have been questioned on the basis of theoretical and experimental grounds [34].
  • It is fully confirmed that the colorless light-activated intermediate recorded by millisecond time-resolved crystallography [Genick, U. K., Borgstahl, G. E. O., Ng, K., Ren, Z., Pradervand, C., et al. (1997) Science 275, 1471-1475] is protonated, nicely matching the spectroscopic features of the photoproduct PYP(M) [35].
  • FAB-MS analysis of the HPLC fractions gave numerous protonated molecular ions ranging from m/z 491 to 2662 [36].


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  16. Two-photon spectroscopy of locked-11-cis-rhodopsin: evidence for a protonated Schiff base in a neutral protein binding site. Birge, R.R., Murray, L.P., Pierce, B.M., Akita, H., Balogh-Nair, V., Findsen, L.A., Nakanishi, K. Proc. Natl. Acad. Sci. U.S.A. (1985) [Pubmed]
  17. Structure of the N intermediate of bacteriorhodopsin revealed by x-ray diffraction. Kamikubo, H., Kataoka, M., Váró, G., Oka, T., Tokunaga, F., Needleman, R., Lanyi, J.K. Proc. Natl. Acad. Sci. U.S.A. (1996) [Pubmed]
  18. Reversible single-molecule photoswitching in the GFP-like fluorescent protein Dronpa. Habuchi, S., Ando, R., Dedecker, P., Verheijen, W., Mizuno, H., Miyawaki, A., Hofkens, J. Proc. Natl. Acad. Sci. U.S.A. (2005) [Pubmed]
  19. Base pairing and mutagenesis: observation of a protonated base pair between 2-aminopurine and cytosine in an oligonucleotide by proton NMR. Sowers, L.C., Fazakerley, G.V., Eritja, R., Kaplan, B.E., Goodman, M.F. Proc. Natl. Acad. Sci. U.S.A. (1986) [Pubmed]
  20. Evidence for a central role for PfCRT in conferring Plasmodium falciparum resistance to diverse antimalarial agents. Johnson, D.J., Fidock, D.A., Mungthin, M., Lakshmanan, V., Sidhu, A.B., Bray, P.G., Ward, S.A. Mol. Cell (2004) [Pubmed]
  21. Effect of protonated 2,4,6-triaminopyrimidine, a tight junction blocker, on intestinal transport in dog ileum in vivo. Krejs, G.J., Seelig, L.L., Fordtran, J.S. Gastroenterology (1977) [Pubmed]
  22. Carrier-mediated jejunal absorption of conjugated bile acids in the guinea pig. Amelsberg, A., Schteingart, C.D., Ton-Nu, H.T., Hofmann, A.F. Gastroenterology (1996) [Pubmed]
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  29. Alkylsulfonates as probes of uncoupling protein transport mechanism. Ion pair transport demonstrates that direct H(+) translocation by UCP1 is not necessary for uncoupling. Jabůrek, M., Varecha, M., Jezek, P., Garlid, K.D. J. Biol. Chem. (2001) [Pubmed]
  30. Characterization of the primary photointermediates of Drosophila rhodopsin. Vought, B.W., Salcedo, E., Chadwell, L.V., Britt, S.G., Birge, R.R., Knox, B.E. Biochemistry (2000) [Pubmed]
  31. The conserved histidine 295 does not contribute to proton cotransport by the glutamate transporter EAAC1. Tao, Z., Grewer, C. Biochemistry (2005) [Pubmed]
  32. Preferential efflux by P-glycoprotein, but not MRP1, of compounds containing a free electron donor amine. Salerno, M., Przewloka, T., Fokt, I., Priebe, W., Garnier-Suillerot, A. Biochem. Pharmacol. (2002) [Pubmed]
  33. THEMATICS: a simple computational predictor of enzyme function from structure. Ondrechen, M.J., Clifton, J.G., Ringe, D. Proc. Natl. Acad. Sci. U.S.A. (2001) [Pubmed]
  34. Infrared evidence that the Schiff base of bacteriorhodopsin is protonated: bR570 and K intermediates. Rothschild, K.J., Marrero, H. Proc. Natl. Acad. Sci. U.S.A. (1982) [Pubmed]
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