HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Brade, V. Articles by Hadding, U. Search for Related Content PubMed Articles by Brade, V. Articles by Hadding, U.

Formation of the C3-Cleaving Properdin Enzyme on Zymosan

Demonstration That Factor D Is Replaceable by Proteolytic Enzymes¹

From the Institut für Medizinische Mikrobiologie der Johannes-Gutenberg-Universität, D-65 Mainz (Germany) and from the Department of Microbiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205

Abstract

During incubation of ZX^d2, an insoluble intermediate of the properdin system, with properdin factors D and B a complex forms, designated ZX, which cleaves purified C3. Factor D is replaceable in this system by proteolytic enzymes, e.g., trypsin, pronase or plasmin. ZX formation with ZX^d2, factor B and factor D or trypsin requires the presence of Mg⁺⁺. ZX complexes formed either with factor D or with trypsin are identical with respect to their stability in the absence of divalent cations and with respect to the decay of the C3-cleaving enzymes. From the data obtained with proteolytic enzymes it is concluded that factor D acts as a protease in the formation of ZX. Sequential studies of ZX formation revealed that factor B binds reversibly to ZX^d2 in the presence of Mg⁺⁺. The resulting ZX^d2 B complex was found to acquire enzymatic activity against C3 after treatment with factor D or trypsin. Our data suggest that in the ZX^d2 system two steps are involved in ZX formation, namely binding of factor B to a receptor on ZX^d2, probably C3b, which occurs only in the presence of Mg⁺⁺, and subsequent proteolytic activation of this complex which is Mg⁺⁺-independent.

Footnotes

¹ This work was supported by the Sonderforschungsbereich 107.

² Reprints may be obtained from Dr. Volker Brade, Institut für Medizinische Mikrobiologie der Johannes-Gutenberg-Universität, D-65 Mainz (Germany).

This article has been cited by other articles:

				J. Sato, J. Schorey, V. A. Ploplis, E. Haalboom, L. Krahule, and F. J. Castellino The Fibrinolytic System in Dissemination and Matrix Protein Deposition During a Mycobacterium Infection Am. J. Pathol., August 1, 2003; 163(2): 517 - 531. [Abstract] [Full Text] [PDF]