Normal human serum subjected to sucrose density gradient analysis exhibited multiple sedimenting species of properdin antigen. Properdin antigen distribution was dependent on serum concentration, ionic strength, temperature, and the presence of C3, and was not dependent on the presence of divalent metal cations or blood coagulation. In mixtures of purified components, properdin sedimented heavier in the presence of C3, C3b, or C3c. Addition of factor B to mixtures containing C3 and properdin was without effect. These data provide insights into earlier discrepancies concerning the sedimentation behavior of partially purified properdin, indicate a propensity of some constituents of the alternative pathway to form protein-protein complexes, and suggest caution in interpretation of immunopathological studies in which properdin deposits are found in the presence of C3.
Properdin- and nephritic factor-dependent C3 convertases: requirement of native C3 for enzyme formation and the function of bound C3b as properdin receptor
The mechanism of action of the C3b inactivator (conglutinogen-activating factor) on its naturally occurring substrate, the major fragment of the third component of complement (C3b)
Observations on the effects of a proteinase from Serratia marcescens on the third component of human complement
The membrane attack mechanism of complement. Reversible interactions among the five native components in free solution
Computer stimulation of sedimentation in the ultracentrifuge. VII. Solutes undergoing indefinite self-association
Complement as a mediator of inflammation. II. Biological properties of anaphylatoxin prepared with purified components of human complement
Computer simulation of sedimentation in the ultracentrifuge. VI. Monomer-tetramer systems in rapid chemical equilibrium
The enzymatic nature of C'1r. Conversion of C'1s to C'1 esterase and digestion of amino acid esters by C'1r
Computer simulation of sedimentation in the ultracentrifuge. IV. Velocity sedimentation of self-associating solutes
Formation and functional significance of a molecular complex derived from the second and the fourth component of human complement
The properdin system and immunity. I. Demonstration and isolation of a new serum protein, properdin, and its role in immune phenomena
ISOLATION OF BETA IF-GLOBULIN FROM HUMAN SERUM AND ITS CHARACTERIZATION AS THE FIFTH COMPONENT OF COMPLEMENT
Temporal studies on the deposition of complement on human colostrum IgA and serum IgG immobilized on methylated silicon
Regulation by membrane sialic acid of beta1H-dependent decay-dissociation of amplification C3 convertase of the alternative complement pathway
Alternative pathway of complement: recruitment of precursor properdin by the labile C3/C5 convertase and the potentiation of the pathway
Requirements for the solubilization of immune aggregates by complement: assembly of a factor B-dependent C3-convertase on the immune complexes
Activation of the alternative complement pathway with rabbit erythrocytes by circumvention of the regulatory action of endogenous control proteins
Requirements for the solubilization of immune aggregates by complement. The role of the classical pathway
Development and application of an enzyme-linked immunosorbent assay for the quantitation of alternative complement pathway activation in human serum
The properdin pathway: an "alternative activation pathway" or a "critical amplification loop" for C3 and C5 activation?
Blood Clotting Disorders
Thrombophilia includes conditions with increased tendency for excessive blood clotting. Blood clotting occurs when the body has insufficient amounts of specialized proteins that make blood clot and stop bleeding. Here is the latest research on blood clotting disorders.