Inflammatory cells degrade inter-alpha inhibitor to liberate urinary proteinase inhibitors.

Journal Article

The relationship between inter-alpha inhibitor (I alpha I) and urinary proteinase inhibitor (UPI) was examined by comparing purified UPI with a proteolytic fragment of I alpha I (I'), and by demonstrating that inflammatory cells produce similar fragments under physiologic conditions. Purified I', derived by chymotrypsin digestion of I alpha I, was similar to UPI in apparent molecular weight (68,000-69,000), amino acid composition, immunoreactivity, and inhibitory activity against trypsin, chymotrypsin, and neutrophil elastase. The production of similar inhibitory fragments by murine peritoneal macrophages, human neutrophils, and a murine mast cell line was quantified. Neutrophils were most efficient at proteolyzing I alpha I. Comparison of the pattern of I alpha I degradation by neutrophil preparations with that by pure enzymes, suggested that both elastase and cathepsin G mediate neutrophil proteolysis of I alpha I. These proteinases may thus be responsible for inflammation-related increases in UPI-like inhibitor levels in vivo.

Full Text

Duke Authors

Cited Authors

  • Pratt, CW; Swaim, MW; Pizzo, SV

Published Date

  • January 1989

Published In

Volume / Issue

  • 45 / 1

Start / End Page

  • 1 - 9

PubMed ID

  • 2463321

International Standard Serial Number (ISSN)

  • 0741-5400

Language

  • eng

Conference Location

  • United States