Abstract
β-endorphin metabolism by CD4+ and CD8+ T cells, and the thymoma cell line, EL4, was investigated. In all three cell types, extracellular β-endorphin was metabolized exclusively by a secreted, metal-dependent, thiol peptidase. The enzyme activity is expressed constitutively in EL4 cells and following activation of CD4+ and CD8+ T cells with anti-CD3 antibody. The enzyme is not one of the proteinases associated with cytolytic T cells and does not appear to be identical with any previously described β-endorphin metabolizing enzyme. The enzyme cleaves β-endorphin at approximately equal rates at either of two sites to yield β-endorphin1-17 (which is γ-endorphin), β-endorphin1-18, β-endorphin18-31 and β-endorphin19-31. Evidence in the literature indicates that these N- and C-terminal peptides which contain, respectively, the opioid and non-opioid receptor binding domains of β-endorphin, are biologically active. Thus, it is likely that this new T cell peptidase has important immunoregulatory activity.
Original language | English (US) |
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Pages (from-to) | 151-161 |
Number of pages | 11 |
Journal | Immunopharmacology |
Volume | 31 |
Issue number | 2-3 |
DOIs | |
State | Published - Mar 1996 |
Keywords
- T cell peptidase
- β-Endorphin metabolism
- γ-Endorphin
ASJC Scopus subject areas
- Pharmacology