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PubMed · 874324

Human factor D of the alternative complement pathway: purification and characterization.

J E Volanakis·R E Schrohenloher·R M Stroud
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Abstract

D was purified to homogeneity from outdated human plasma by successive chromatography on Bio Rex 70, Sephadex G-200, Bio Rex 70, and Sephadex G-75. Column fractions were monitored for D activity by a hemolytic diffusion plate assay. The overall yield was approximately 4% by activity. A m.w. of 22,900 daltons was established by sedimentation equilibrium. Amino acid analyses have been obtained and Isoleucine has been determined as the NH2-terminus. Incubation of D with purified B and CoVF in the presence of Mg++ resulted in cleavage of B, as judged by SDS-polyacrylamide gel electrophoresis and immunoelectrophoresis. D hydrolyzed certain synthetic amino acid esters of arginine, lysine, and tyrosine. Benzoyl-L-arginine methyl esters (BAME) was the most sensitive substrate for D among those tested. The substrate profile of D was dinstinct when compared to that of CIs, CIr, plasmin, urokinase, and trypsin. Both the enzymatic and hemolytic activity of D were irreversibly inhibited by treatment with 10 mM DFP as well as by reduction and alkylation.

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Blood ProteinsComplement System ProteinsEsterasesHumansJournal ArticleResearch Support, U.S. Gov't, P.H.S.

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J E Volanakis, R E Schrohenloher, R M Stroud. 1977. Human factor D of the alternative complement pathway: purification and characterization.. https://pubmed.ncbi.nlm.nih.gov/874324/

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