Synthesis and Structure-activity Relationship of N-(Acyl)muramoyl-dipeptides

Abstract

A variety of N-(acyl)muramoyl-dipeptides were synthesized and their immunoadjuvant activities were examined on the induction of delayed-type hypersensitivity to N-acetyl-L-tyrosine-3-azobenzene-4'-arsonate in guinea pigs. It was found that introduction of acyl groups to the 2-amino group in muramoyl-L-valyl- or -L-seryl-D-isoglutamine reduced the activity with the increasing length of the acyl group, although all N-(acyl)muramoyl-L-alanyl-D-isoglutamines were active as an adjuvant. The results suggest that development of the adjuvant activity of N-(acyl)muramoyldipeptides is closely related to both the length of the acyl group and the bulkiness of the peptide moiety.