Determination of carboxypeptidase A using N-acetyl-phenylalanyl-3-thiaphenylalanine as substrate: application to a direct serum assay

Anal Biochem. 1987 Feb 15;161(1):219-25. doi: 10.1016/0003-2697(87)90674-9.

Abstract

N-Acetyl-L-phenylalanyl-L-3-thiaphenylalanine has been shown to be a substrate for carboxypeptidase A. Hydrolysis of the compound obeys Michaelis-Menten kinetics with a KM of 0.22 mM and a kcat of 6720 min-1 at 22 degrees C. A colorimetric assay, employing Ellman's reagent to detect the thiophenol released upon cleavage of the peptide, has been developed. The assay can be used for the direct determination of carboxypeptidase A in serum.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carboxypeptidases / analysis*
  • Carboxypeptidases / blood
  • Carboxypeptidases A
  • Cattle
  • Colorimetry / methods*
  • Dipeptides
  • Humans
  • Hydrolysis
  • Kinetics
  • Pancreatitis / diagnosis
  • Pancreatitis / enzymology
  • Substrate Specificity

Substances

  • Dipeptides
  • N-acetylphenylalanyl-3-thiaphenylalanine
  • Carboxypeptidases
  • Carboxypeptidases A