Aminopeptidase activity in human nasal mucosa

Kimihiro Ohkubo, James N. Baraniuk, Robert Hohman, Marco Merida, Louis B. Hersh, Michael A. Kaliner

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Background: Aminopeptidases activate bradykinin and degrade many inflammatory peptides. Objective: The objective of this study was to identify the types of aminopeptidase activities in human nasal mucosa. Methods: Human nasal mucosa was homogenized (n = 12), and cytoplasmic (S2) and membrane- rich (P2) fractions were obtained. Several aminopeptidase (Ap) activities were defined by (1) substrate specificity with leucine-enkephalin (leu-Ap) and alanine-nitroanilide (ala-Ap), (2) inhibitor studies with puromycin and bestatin, (3) enzyme activity histochemistry (zymography), (4) immunohistochemistry, and (5) gel electrophoresis. Human volunteers had methacholine, histamine, and allergen nasal provocations to determine the mechanisms controlling nasal aminopeptidase secretion in vivo. Results: P2 was the largest reservoir of puromycin-resistant aminopeptidase activity (630 pmol leu-enk/min/mg protein). S2 contained 32 pmol leu-enk/min/mg activity, with 80% representing puromycin-resistant activity and 20% puromycin- sensitive aminopeptidase (PS-Ap). Ala-Ap was detected in both P2 and S2 fractions and was localized by zymography to epithelial and gland cells. Anti-rat brain-soluble PS-Ap IgG detected immunoreactive material in epithelium, glands, and endothelium. In nasal provocation studies, leu-AP correlated with glandular exocytosis but not vascular leak. Conclusions: The predominant aminopeptidase in human nasal epithelial and submucosal gland cells was membrane-bound puromycin-resistant aminopeptidase. A novel soluble puromycin-resistant aminopeptidase and lower amounts of soluble PS-Ap were also detected.

Original languageEnglish
Pages (from-to)741-750
Number of pages10
JournalJournal of Allergy and Clinical Immunology
Volume102
Issue number5
DOIs
StatePublished - 1998

Funding

FundersFunder number
National Institute on Drug AbuseR01DA002243

    Keywords

    • Aminopeptidase M
    • Bradykinin
    • Enkephalin-degrading aminopeptidase
    • Glandular secretion
    • Puromycin sensitive aminopeptidase
    • Rhinitis

    ASJC Scopus subject areas

    • Immunology and Allergy
    • Immunology

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