Synthesis of N alpha-protected aminoacyl 7-amino-4-methyl-coumarin amide by phosphorous oxychloride and preparation of specific fluorogenic substrates for papain

Pept Res. 1996 Mar-Apr;9(2):92-6.

Abstract

We report an improved procedure for the synthesis of fully protected aminoacyl 7-amino-4-methylcoumarin amide (MCA) employing the phosphorous oxychloride anhydride method. Seven Boc-X-MCA [where X = Arg(NG Tos), Cys(S-Bzl), Thr(O-Bzl), Ser(O-Bzl), Phe, Leu and Gly] and Z-Tyr(O-Me) were synthesized using this procedure, with yields ranging from 50% to 75%. These aminoacyl-MCA derivatives were employed for the synthesis of epsilon-NH2-caproyl-Leu-X-MCA, a fluorescent peptide series, which were assayed as papain substrates. All of them were completely hydrolyzed by papain, indicating that all of the Boc-X-MCA derivatives obtained were practically free of racemization. Since epsilon-NH2-Caproyl-Leu-(S-Bzl)Cys-MCA is very susceptible to hydrolysis by papain, quite resistant to hydrolysis by chymotrypsin and not hydrolyzed by trypsin, it is recommended for assays of thiol-proteinases in which specificity is required.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / chemistry*
  • Coumarins / chemistry*
  • Dipeptides / chemistry*
  • Fluorescent Dyes / chemical synthesis*
  • Papain / metabolism*
  • Phosphorus / chemistry
  • Phosphorus Compounds*

Substances

  • Amino Acids
  • Coumarins
  • Dipeptides
  • Fluorescent Dyes
  • Phosphorus Compounds
  • Phosphorus
  • phosphoryl chloride
  • Papain