Kerr constants of random coil polypeptides

Summary

Calculations of average molar Kerr constants <_mK> of polypeptides of the twenty natural α-aminoacids in the random coil state are presented. The computation was carried out according to the Rotational Isomeric States model with the values of energies, dipole moments and optical anisotropies of the repeating units reported elsewhere. In the case of homopolypeptides, the ratios <_mK>/x extrapolated to x^→∞ range approximately from −6000 to +5000 in units of 10⁻²⁷V⁻²m⁵mol⁻¹. Results obtained for ten actual proteins and three enzymes in the random coil state are also reported; their values of <_mK>/x are very sensitive to the kind of aminoacid residues and to the sequence of those residues.