RANDOM COIL DIMENSIONS OF METHYLATED POLYPEPTIDES.

Abstract

The random coil dimensions of polysarcosine and poly- alpha -aminoisobutyric acid have been evaluated using both theoretical and experimental methods. Theoretical values for characteristic ratios were derived from the ( phi , psi ) potential energy maps for the cis and trans isomers of N// alpha -acetylsarcosine N,N-dimethylamide and for N// alpha -acetyl- alpha -aminoisobutyryl N-methylamide. Experimental values were derived from viscosity data in various solvents. For polysarcosine in glacial acetic acid, the experimentally derived characteristic ratio agreed with the theoretically derived value for the trans isomer. From the lower ratios observed using water and particularly chloroform, t..