Solutions, polyglutamates

Effect of pH on the Conformation of a-Helical Secondary Structures The unfolding of the a helix of a polypeptide to a randomly coiled conformation is accompanied by a large decrease in a property called its specific rotation, a measure of a solution s capacity to rotate plane-polarized light. Polyglutamate, a polypeptide made up of only l-G1u residues,... 

Scheme 10 Polyglutamic Acid Dendrons by Solution Synthesis 161...

Other Variables. The effect of the polypeptide molecular weight upon a has not yet been conclusively established for any polypeptide-organic solvent system. Recent extensive studies of the charge-induced transition of polyglutamic acid in aqueous solution have shown an increase in a with a reduction in molecular weight 15). Similarly the influence of polypeptide solute concentration is not yet clear, though Ackermann and Riiterjans 1) have demonstrated a remarkably large effect of this variable upon AH0 in PBG. Neither of these points is discussed further in the present paper. 

This polymer was used as a model for polyglutamic acid since a few lysine residues were needed for conjugation with the fluorescent dyes there are too few lysine residues to alter the behavior of the glutamic acid residues. The coil form has a high degree of Brownian motion in solution and therefore little rigidity [p22(F) = 0.015]. [p22(F) is the polarization of... 

FIG. 6.8 Observed r-tc band and the constituents, as determined by a peak-fitting procedure for the solution and as a prepared LBK film of polyglutamate 8. 

From the viscosity measurements in dichloroacetic acid the molecular weights of polyglutamates were estimated. The solutions were prepared by weighing the polymer and solvent in a stoppered bottle. After shaking slowly on a magnetic stirrer for long time, the solutions were put carefully into the cell, which was having parallel sides 2mm apart. Then the top of the capillary of the cell was sealed to prevent the... 

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