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Environ Health Perspect. 1980 April; 35: 165–169.
PMCID: PMC1568461
Articles

Angiotensin-converting enzyme: I. New strategies for assay

Abstract

The disposition of converting enzyme (kininase II) on the luminal surface of pulmonary endothelial cells is well established. Further, it is known that there is a net conversion of angiotensin I into angiotensin II as blood passes through the lungs. However, little is known about modulations of converting enzyme activity that may arise through, e.g., changes in the quality of inhalants, blood flow, or blood oxygenation. There are few data on the effects of lung disease. A major barrier to studies to examine for pathophysiologic modulations of converting enzyme is that of assay. The enzyme can be measured in terms of the rate of formation of angiotensin II from a known quantity of angiotensin I. However, both peptides are biologically active, and lungs contain other enzymes capable of degrading them. We have developed a series of radiolabeled, acylated tripeptides to improve our ability to examine for changes in the net converting enzyme of intact lungs. The enzyme, a dipeptidyl carboxypeptidase, is capable of removing C-terminal dipeptides from a variety of oligopeptides. We have prepared benzoyl-Gly-Gly-Gly (I), benzoyl-Pro-Phe-Arg (II), benzoyl-Gly-His-Leu (III), benzoyl-Phe-Ala-Pro (IV), and benzoyl-Phe-His-Leu (V), each containing a 3H-atom in the para position of the benzoyl moiety. Substrates I and III have been used previously in photometric assays of low sensitivity. II is the acylated C-terminal tripeptide of bradykinin, IV is an acylated tripeptide analog of BPP5a (<Glu-Lys-Trp-Ala-Pro) and V is the acylated C-terminal tripeptide of angiotensin I. These substrates can be used in vitro or in vivo to measure converting enzyme. The 3H-labeled product is separable by partitioning between an organic solvent and acidified aqueous solution. The product is quantified by scintillation counting of the organic phase. The choice of substrate depends on the goals of the experiment: substrate I or III when wide variations in substrate concentrations are needed but high sensitivity is not; substrate IV when high sensitivity is needed.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Ryan JW, Ryan US. Pulmonary endothelial cells. Fed Proc. 1977 Dec;36(13):2683–2691. [PubMed]
  • Caldwell PR, Seegal BC, Hsu KC, Das M, Soffer RL. Angiotensin-converting enzyme: vascular endothelial localization. Science. 1976 Mar 12;191(4231):1050–1051. [PubMed]
  • Ward PE, Erdös EG, Gedney CD, Dowben RM, Reynolds RC. Isolation of membrane-bound renal enzymes that metabolize kinins and angiotensins. Biochem J. 1976 Sep 1;157(3):643–650. [PubMed]
  • Wigger HJ, Stalcup SA. Distribution and development of angiotensin converting enzyme in the fetal and newborn rabbit. An immunofluorescence study. Lab Invest. 1978 May;38(5):581–585. [PubMed]
  • Ryan JW, Day AR, Schultz DR, Ryan US, Chung A, Marlborough DI, Dorer FE. Localization of angiotensin converting enzyme (kininase II). I. Preparation of antibody-hemeoctapeptide conjugates. Tissue Cell. 1976;8(1):111–124. [PubMed]
  • Ryan JW, Ryan US, Schultz DR, Whitaker C, Chung A. Subcellular localization of pulmonary antiotensin-converting enzyme (kininase II). Biochem J. 1975 Feb;146(2):497–499. [PubMed]
  • Ryan US, Ryan JW, Whitaker C, Chiu A. Localization of angiotensin converting enzyme (kininase II). II. Immunocytochemistry and immunofluorescence. Tissue Cell. 1976;8(1):125–145. [PubMed]
  • Ryan US, Clements E, Habliston D, Ryan JW. Isolation and culture of pulmonary artery endothelial cells. Tissue Cell. 1978;10(3):535–554. [PubMed]
  • Soffer RL. Angiotensin-converting enzyme and the regulation of vasoactive peptides. Annu Rev Biochem. 1976;45:73–94. [PubMed]
  • Fisher GH, Ryan JW, Martin LC, Pena GA. Structure-activity relationships for kininase II inhibition by lower homologs of the bradykinin potentiating peptide BPP9a. Adv Exp Med Biol. 1979;120B:651–663. [PubMed]
  • Ryan JW, Chung A, Ammons C, Carlton ML. A simple radioassay for angiotensin-converting enzyme. Biochem J. 1977 Nov 1;167(2):501–504. [PubMed]
  • Ryan JW, Chung A, Martin LC, Ryan US. New substrates for the radioassay of angiotensin converting enzyme of endothelial cells in culture. Tissue Cell. 1978;10(3):555–562. [PubMed]
  • Ryan JW, Niemeyer RS, Goodwin DW, Smith U. Metabolism of [8-L-[14C] phenylalanine]-angiotensin I in the pulmonary circulation. Biochem J. 1971 Dec;125(3):921–923. [PubMed]
  • Ryan JW, Smith U, Niemeyer RS. Angiotensin I: metabolism by plasma membrane of lung. Science. 1972 Apr 7;176(4030):64–66. [PubMed]
  • Dorer FE, Kahn JR, Lentz KE, Levine M, Skeggs LT. Hydrolysis of bradykinin by angiotensin-converting enzyme. Circ Res. 1974 Jun;34(6):824–827. [PubMed]
  • Dorer F, Ryan JW, Stewart JM. Hydrolysis of bradykinin and its higher homologues by angiotensin-converting enzyme. Biochem J. 1974 Sep;141(3):915–917. [PubMed]
  • Dorer FE, Kahn JR, Lentz KE, Levine M, Skeggs LT. Purification and properties of angiotensin-converting enzyme from hog lung. Circ Res. 1972 Sep;31(3):356–366. [PubMed]
  • Ondetti MA, Williams NJ, Sabo EF, Pluscec J, Weaver ER, Kocy O. Angiotensin-converting enzyme inhibitors from the venom of Bothrops jararaca. Isolation, elucidation of structure, and synthesis. Biochemistry. 1971 Oct 26;10(22):4033–4039. [PubMed]
  • Cushman DW, Pluscec J, Williams NJ, Weaver ER, Sabo EF, Kocy O, Cheung HS, Ondetti MA. Inhibition of angiotensin-coverting enzyme by analogs of peptides from Bothrops jararaca venom. Experientia. 1973 Aug 15;29(8):1032–1035. [PubMed]
  • Chiu AT, Ryan JW, Stewart JM, Dorer FE. Formation of angiotensin III by angiotensin-converting enzyme. Biochem J. 1976 Apr 1;155(1):189–192. [PubMed]
  • Cushman DW, Cheung HS, Sabo EF, Ondetti MA. Design of potent competitive inhibitors of angiotensin-converting enzyme. Carboxyalkanoyl and mercaptoalkanoyl amino acids. Biochemistry. 1977 Dec 13;16(25):5484–5491. [PubMed]
  • Dorer FE, Kahn JR, Lentz KE, Levine M, Skeggs LT. Kinetic properties of pulmonary angiotensin-converting enzyme. Hydrolysis of hippurylglycylglycine. Biochim Biophys Acta. 1976 Mar 11;429(1):220–228. [PubMed]

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