Hydrolysis of biological peptides by human angiotensin-converting enzyme-related carboxypeptidase

J Biol Chem. 2002 Apr 26;277(17):14838-43. doi: 10.1074/jbc.M200581200. Epub 2002 Jan 28.


Human angiotensin-converting enzyme-related carboxypeptidase (ACE2) is a zinc metalloprotease whose closest homolog is angiotensin I-converting enzyme. To begin to elucidate the physiological role of ACE2, ACE2 was purified, and its catalytic activity was characterized. ACE2 proteolytic activity has a pH optimum of 6.5 and is enhanced by monovalent anions, which is consistent with the activity of ACE. ACE2 activity is increased approximately 10-fold by Cl(-) and F(-) but is unaffected by Br(-). ACE2 was screened for hydrolytic activity against a panel of 126 biological peptides, using liquid chromatography-mass spectrometry detection. Eleven of the peptides were hydrolyzed by ACE2, and in each case, the proteolytic activity resulted in removal of the C-terminal residue only. ACE2 hydrolyzes three of the peptides with high catalytic efficiency: angiotensin II () (k(cat)/K(m) = 1.9 x 10(6) m(-1) s(-1)), apelin-13 (k(cat)/K(m) = 2.1 x 10(6) m(-1) s(-1)), and dynorphin A 1-13 (k(cat)/K(m) = 3.1 x 10(6) m(-1) s(-1)). The ACE2 catalytic efficiency is 400-fold higher with angiotensin II () as a substrate than with angiotensin I (). ACE2 also efficiently hydrolyzes des-Arg(9)-bradykinin (k(cat)/K(m) = 1.3 x 10(5) m(-1) s(-1)), but it does not hydrolyze bradykinin. An alignment of the ACE2 peptide substrates reveals a consensus sequence of: Pro-X((1-3 residues))-Pro-Hydrophobic, where hydrolysis occurs between proline and the hydrophobic amino acid.

MeSH terms

  • Amino Acid Sequence
  • Angiotensin-Converting Enzyme 2
  • Carboxypeptidases / metabolism*
  • Catalysis
  • Chromatography, High Pressure Liquid
  • Chromatography, Ion Exchange
  • Humans
  • Hydrogen-Ion Concentration
  • Hydrolysis
  • Kinetics
  • Peptides / metabolism*
  • Peptidyl-Dipeptidase A
  • Recombinant Proteins / metabolism
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Spectrophotometry, Ultraviolet


  • Peptides
  • Recombinant Proteins
  • Carboxypeptidases
  • Peptidyl-Dipeptidase A
  • ACE2 protein, human
  • Angiotensin-Converting Enzyme 2