ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The solvent-and pH-induced conformational changes are examined in order to investigate the influence of benzyl group. Polymer was prepared via N∊-benzyloxycarbonyl, N∊-benzyl-Nα-carboxy-L-lysine anhydride. The resulting poly (N∊-benzyloxycarbonyl, N∊-benzyl-L-lysine) was obtained in high yield and had a high molecular weight. The protected polymer was removed into poly (N∊-benzyl-L-lysine) by treating it with hydrogen bromide. From the results of the ORD and CD, the protected polymer has a righthanded α-helix, showing [m′]233 = -10,300, [θ]220 = -27,600 and [θ]207 = -25,100 in dioxane. The breakdown of the helical conformation is found to occur at 8% dichloroacetic acid in chloroform-dichloroacetic acid mixture. In the pH range 3.35-6.90, poly (N∊-benzyl-L-lysine) is in a random coil structure. In the pH range 7.50-13.0, the polypeptide has a right-handed α-helix structure; [m′]233 = -12,000, [0]220 = -27,200, and [0]207 = -27,000. In comparison with poly-L-lysine, the coil-to-helix transition is observed at lower pH range in 50% n-propanol. Above pH 8 by heating, the α ⇀ β transition of poly (N∊-benzyl-L-lysine) is not observed in an aqueous media.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1972.360110610
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