Table 2. Parameters for analysis of the L process.

(a) amino acid in water								(b) amino acid in collagen aqueous solution
amino acid	x(%)	τL(ps)	τa(ps)	a[Å]	b[Å]	εs		ccollagen(wt%)	τa (ps)
glycine	3.0	72	74	3.67	2.11	120	91.3	4.0	74
β-alanine	3.0	107	108	4.30	2.21	135	88.2	4.0	112
L-serine	3.0	123	114	3.93	2.66	123	83.3	0.4	120
L-arginine	1.0	309	282	6.30	2.68	114	74.4	0.4	309

(a) Observed dielectric relaxation time of the L process, τ_L, in the aqueous solutions of amino acids and calculated relaxation time, τ_a, assuming that the origin of the L process is rotational diffusion of the amino acid molecule. All the parameters used to calculate the values of τ_a with Perrin’s equation (Eq. 2) are also listed in this table. In our calculations, we did not account for the effect of hydrated water surrounding the amino acid molecule because the volume occupied by such water molecules is not well defined. Clearly, the values of observed relaxation times, τ_L, for glycine and β-alanine are similar to those of τ_a. However, the values of τ_a for L-serine and L-arginine are somewhat less than those obtained experimentally. Because these amino acids have long and charged residuals, it can be assumed that such amino acids are surrounded by a larger amount of hydrated water compared to glycine and β-alanine. For this reason, the experimental relaxation times are greater than the relaxation times estimated using Eq. 2. (b) Collagen concentration, c_collagen, and observed relaxation time of the L process, τ_L, in the aqueous solutions of collagen with an amino acid. Note that the values of τ_L in (b) and those in (a) are identical. This fact suggests that the local viscosity of the aqueous solution with collagen is the same as that of pure water.