Multiple Nature of the Third Component of Guinea-Pig Complement II. SEPARATION AND DESCRIPTION OF TWO ADDITIONAL FACTORS β AND <em>d</em>; PREPARATION AND CHARACTERIZATION OF FOUR INTERMEDIATE PRODUCTS.

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. [ABSTRACT FROM AUTHOR]