A heterodimeric protein complex that catalyzes the cleavage of complement components C3 and C5, and acts in the classical pathway of complement activation; consists of one monomer of C2a and one monomer of C4b; C2a is the catalytic subunit, but cannot catalyze cleavage alone.
CoA-synthesizing protein complex
CSK-GAP-A.p62 complex
cyclic-nucleotide phosphodiesterase complex
cytochrome complex +
cytosolic tRNA wobble base thiouridylase complex
DNA helicase complex +
DNA ligase III-XRCC1 complex
DNA ligase IV complex
DNA repair complex +
DNA topoisomerase type II (double strand cut, ATP-hydrolyzing) complex +