the initial high amounts of n-l-alanyl-l , l-cystine and n-glycyl-l , l-cystine as well as the prompt increase of the constituent free amino acids alanine , glycine and cystine strongly suggest that the peptide disappearance is mainly due to a very fast two-step hydrolysis in the extracellular compartment , presumably catalyzed by soluble and/or plasma membrane bound peptidases .
C0002520
amino acids
C0001898
alanine