Copolymerization kinetics of <i>N</i>‐carboxyanhydrides of some α‐amino acids: Influence of nature of amino acids

Abstract

Abstract Studies on copolymerization kinetics of N ‐carboxyanhydride (NCA) of O ‐acetyl‐ L ‐tyrosine (T) with NCAs of L ‐valine (V) and glycine (G) were carried out in dioxane at 25°C with n ‐butylamine as initiator. The reactivity ratios for the VT system were found to be r V : r T :0.57:0.22; and for the GT system, r G : r T :0.26:0.42. A comparison of this data with that obtained when L ‐analine was used in place of L ‐valine or glycine showed that in the three systems, the reactivity ratio of the amino acid residue with a greater tendency to form ordered secondary structure was greater than that of its comonomer. Among the variable comonomers (glycine, L ‐alanine, L ‐valine) of O ‐acetyl‐ L ‐tyrosine, it is again L ‐alanine, whose tendency to form helical structure is very high, that has the greater reactivity ratio.