Functional Relationship of Factor B in the Properdin System to C3 Proactivator of Human Serum

摘要: Summary Factor B in the properdin system is a heatlabile protein requiring, addition to properdin, other serum factors, and Mg 2+ , for formation of complex with zymosan which preferentially inactivates C3 later acting components. β-pseudoglobulin distinct from C2. Evidence has been presented that factor functionally identical an independently isolated protein, proactivator (C3PA). These observations serve both identify characterize and, conjunction earlier evidence, establish as alternate pathway components, independent C1, C4