MOLECULAR ROTATIONS OF N-ALPHA-ACYL-L-LYSINES AT VARIOUS PH VALUES

Molecular rotations of N-alpha-acyl-L-lysines were determined in water and in water containing various amounts of HCl or NaOH. The acyl grou ps were formyl, acetyl, propionyl, and butyryl. Each N-alpha-acyl-L-ly sine exhibited more negative rotation in HCl or NaOH solution than in water. The plot of molecular rotation against amount of HCl or NaOH re sembled that of a D-alpha-amino acid even though N-alpha-acyl-lysine w as of L-form. The reason for this is discussed from the standpoint of steric factors. N-epsilon-Acyl-L-lysines corresponding to the N-alpha- acyl-L-lysines were synthesized as reference compounds. It was found t hat water-soluble N-epsilon-acyl-L-lysines can be easily prepared by a cylation of the Cu complex solution of L-lysine hydrochloride in the p resence of triethylamine. The molecular rotation plots for N-epsilon-a cyl-L-lysines were typical of L-a-amino acids.