the new substrate , boc-nle-gln-leu-gly-arg-amino methyl coumarin ( amc ) was synthesized by coupling boc-nle-gln-leu-gly to arg-amc in solution . p-toluenesulfonic acid was added to the coupling mixture to improve the solubility of the arginine derivative and avoid the need for covalent protection .
C0017797
gln
C0002520
amc