has role is protonated form of N-acetyl-beta-D-muramoyl-L-alanyl-D-isoglutamine(1-) glycopeptide immunological adjuvant muramyl dipeptide A glycopeptide that is <em>N</em>-propionyl-<small>L</small>-alanyl-<small>D</small>-α-glutamine in which the pro-<i>R</i> hydrogen of the propionyl group has been replaced by the oxygen at position 3 of 2-acetamido-2-deoxy-β-<small>D</small>-glucopyranose. A peptidoglycan constituent of both Gram-positive and Gram-negative bacteria. CHEBI:59414