Proteolytic inactivation of alpha 1-proteinase inhibitor and alpha 1-antichymotrypsin by oxidatively activated human neutrophil metalloproteinases.
Human neutrophils use the H2O2-myeloperoxidase-chloride system to generate chlorinated oxidants capable of activating metalloproteinase zymogens that hydrolyze not only native and denatured collagens, but also the serine proteinase inhibitor (serpin) alpha 1-proteinase inhibitor (alpha 1 PI). To identify the metalloenzyme that hydrolyzes and inactivates alpha 1 PI, neutrophil releasates were chromatographed over gelatin-Sepharose and divided into fractions containing either progelatinase or procollagenase. The gelatinase-containing fraction cleaved alpha 1 PI in a manner inhibitable by native type V, but not type I, collagen. Conversely, while the collagenase-containing fraction also cleaved alpha 1 PI, this activity was inhibited by type I, but not type V, collagen. Because type I and V collagens are competitive substrates for collagenase and gelatinase, respectively, each of the metalloproteinase zymogens were purified to apparent homogeneity and examined for alpha 1 PI-hydrolytic activities. Both purified gelatinase and collagenase inactivated alpha 1PI by hydrolyzing the serpin within its active-site loop at the Phe352-Leu353 and Pro357-Met358 bonds, albeit with distinct kinetic properties. Furthermore, purified collagenase, but not gelatinase, cleaved a second serpin, alpha 1-antichymotrypsin, by hydrolyzing the Ala362-Leu363 bond within its active-site loop. These data demonstrate that human neutrophils use chlorinated oxidants to activate collagenolytic metalloproteinases whose substrate specificities can be extended to members of the serpin superfamily.
Desrochers
P E
PE
Department of Medicine, University of Michigan Medical Center, Ann Arbor 48109.
Mookhtiar
K
K
Van Wart
H E
HE
Hasty
K A
KA
Weiss
S J
SJ
D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors; D004792:Enzyme Precursors / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D008666:Metalloendopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D003012:Microbial Collagenase / Q000378:metabolism; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D010084:Oxidation-Reduction; D000514:alpha 1-Antichymotrypsin / Q000378:metabolism*; D000515:alpha 1-Antitrypsin / Q000378:metabolism*
D004791:Enzyme Inhibitors; D004792:Enzyme Precursors; D000514:alpha 1-Antichymotrypsin; D000515:alpha 1-Antitrypsin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D008666:Metalloendopeptidases; D003012:Microbial Collagenase