{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,3]],"date-time":"2026-04-03T15:13:51Z","timestamp":1775229231372,"version":"3.50.1"},"reference-count":0,"publisher":"Rockefeller University Press","issue":"2","content-domain":{"domain":["rupress.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1974,2,1]]},"abstract":"<jats:p>The activity of properdin factor D was measured by the generation of the hemolytically active cellular intermediate, EAC43B(D), bearing the C3b-dependent alternate pathway C3 convertase. Treatment of factor D with DFP prevented formation of EAC43B(D); thus, a serine esterase is essential for the generation of the alternate pathway C3 convertase, a situation analogous to the role of C1 in the formation of the classical C3 convertase, C42. The definition of factor D as a serine esterase prompted a search for its proenzyme form, and resulted in the chromatographic isolation from plasma of a single peak of trypsin-inducible factor D activity, distinct from activated factor D. Analytical gel filtration indicated an apparent mol wt of 25,000. This protein from which trypsin elaborated factor D activity, as assessed by the formation of EAC43B(D), the generation of the CoVF-dependent C3 convertase, and the cleavage of factor B in the presence of C3b, was designated \"precursor factor D.\" The DFP resistance of precursor factor D, and the susceptibility of its trypsin-activated form to inactivation by DFP is analogous to the behavior of other plasma serine esterases, including C1.<\/jats:p>","DOI":"10.1084\/jem.139.2.355","type":"journal-article","created":{"date-parts":[[2004,6,23]],"date-time":"2004-06-23T23:23:31Z","timestamp":1088033011000},"page":"355-366","update-policy":"https:\/\/doi.org\/10.1084\/jem.crossmarkpolicy","source":"Crossref","is-referenced-by-count":78,"title":["PROPERDIN FACTOR D: CHARACTERIZATION OF ITS ACTIVE SITE AND ISOLATION OF THE PRECURSOR FORM"],"prefix":"10.1084","volume":"139","author":[{"given":"Douglas T.","family":"Fearon","sequence":"first","affiliation":[{"name":"From the Departments of Medicine, Harvard Medical School and the Robert B. Brigham Hospital, Boston, Massachusetts 02120"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"K. Frank","family":"Austen","sequence":"additional","affiliation":[{"name":"From the Departments of Medicine, Harvard Medical School and the Robert B. Brigham Hospital, Boston, Massachusetts 02120"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shaun","family":"Ruddy","sequence":"additional","affiliation":[{"name":"From the Departments of Medicine, Harvard Medical School and the Robert B. Brigham Hospital, Boston, Massachusetts 02120"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"291","published-online":{"date-parts":[[1974,2,1]]},"container-title":["The Journal of Experimental Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/rupress.org\/jem\/article-pdf\/139\/2\/355\/1655920\/355.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/rupress.org\/jem\/article-pdf\/139\/2\/355\/1655920\/355.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,7,24]],"date-time":"2023-07-24T21:14:13Z","timestamp":1690233253000},"score":1,"resource":{"primary":{"URL":"https:\/\/rupress.org\/jem\/article\/139\/2\/355\/6522\/PROPERDIN-FACTOR-D-CHARACTERIZATION-OF-ITS-ACTIVE"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1974,2,1]]},"references-count":0,"journal-issue":{"issue":"2","published-print":{"date-parts":[[1974,2,1]]}},"URL":"https:\/\/doi.org\/10.1084\/jem.139.2.355","relation":{},"ISSN":["1540-9538","0022-1007"],"issn-type":[{"value":"1540-9538","type":"electronic"},{"value":"0022-1007","type":"print"}],"subject":[],"published":{"date-parts":[[1974,2,1]]}}}