Multiple nature of the third component of guinea-pig complement. II. Separation and description of two additional factors beta and d; preparation and characterization of four intermediate products

Abstract

Two factors essential for the lysis of EAC′₁₄₂ cells are described and designated as β and d. These factors are distinct from the C′₃-subunits a, b and c described earlier; they can be separated by chemical procedures. A simple assay method for both factors is given. Four highly reactive intermediates, EAC′_142,a; EAC′_142,a,b; EAC′_142,a,b,β and EAC′_142,a,b,β,c can be prepared and characterized by their lytic reactivity pattern against different systems of incomplete C′₃. Evidence is presented that the subunits of the C′₃-system interact with EAC′₁₄₂ in a sequential order corresponding to the formula a—b—β—c—d.