Ethanol Gramicidin

X-ray diffraction studies on gramicidin commenced as early as 1949 218-219> and this early work pointed to a helical structure 220). Recent work by Koeppe et al. 221) on gramicidin A crystallised from methanol (/%) and ethanol (.P212121) has shown that the helical channel has a diameter of about 5 A and a length of about 32 A in both cases. The inclusion complexes of gramicidin A with CsSCN and KSCN (P212121) have channels that are wider (6-8 A) and shorter (26 A) than the uncomplexed dimer 221 222). Furthermore there are two cation binding sites per channel situated either 2.5 A from either end of the channel or 2.5 A on each side of its centre 222) Unfortunately these data do not permit a choice to be made from the helical models (i)—(iv) and it is not certain if the helical canals studied are the same as those involved in membrane ion transport. 

Gramicidin exhibits strong fluorescence in 95% ethanol. The excitation maximum is at 286 nm and the emission maximum is at 337 nm. The fluorescence intensity was linear with respect to concentration in solution51. 

The diffusion constants for the gramicidin complex were determined in acetic acid and ethanol solution75. The molecular weight range of gramicidin was calculated as 2800-5000. 

Derechin and coworkers noted the anomalous behavior of gramicidin A in absolute ethanol79. The apparent partial specific volume increased with decreasing concentration of gramicidin. The same was not true for aqueous-ethanol solutions. 

Figure 3. Stereoview (backbone atoms only) of the gramicidin A antiparallel double-stranded f 5 6-helix crystallized from ethanol. Narrow lines indicate hydrogen bonds. (Reproduced with permission from reference 33. Copyright...

Ethinylestradiol Ethanedisulfonic acid Caramiphen edisylate Ethanol Alibenol Benoxinate HCI Bufexa mac Clobazam Clofibrate Dicyclomine HCI Ethionamide Ethoheptazine Etiroxate Exalamide Feprazone Floredil HCI Flurbiprofen Gramicidin Heptabarbitol Ibuprofen Ibuproxam Insulin Ketoprofen Lofexidine HCI Mebeverine HCI Meperidine HCI Methitural... 

Gramicidin A [Bacillus brevis] 1883.33 methanol, ethanol, pyridine, acetone antibiotic peptide ionophore forming channels for and alkali cations... 

Materials. Dioleoyl phophatidyl choline (DOPC) was purchased from Avanti Polar Lipids Inc. (Pelham, AL) and was stored at -78°C under nitrogen as a 20 mg/ml solution in chloroform. All other chemicals were purchased from Sigma Chemical Co. (St. Louis, MO) and used without further purification. Solutions of DOPC in decane were prepared fresh daily by evaporating the chloroform from an aliquot of the DOPC stock and replacing the solvent with an equal volume of decane. Alamethicin, gramicidin D, and valino-mycin were stored at 4°C as 1 mM solutions in ethanol. 

Similar results were obtained with Gramicidin D in the concentration range 0.1 - 10 yM. The latter value is probably overestimated since the drug is not so soluble in ethanol. A possible time-dependent effect of the drugs was studied, but not significant effect could be detected within 6 hours from beginnig of the experiments. ... 

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