_EC 3.4.21.43 Classical-complement-pathway C3/C5 convertase. 5 PDB entries  
EC 3.-.-.- Hydrolases. [17,508 PDB entries]
EC 3.4.-.- Acting on peptide bonds (peptide hydrolases). [5,631 PDB entries]
EC 3.4.21.- Serine endopeptidases. [2,051 PDB entries]
EC 3.4.21.43 Classical-complement-pathway C3/C5 convertase. [5 PDB entries]    
2i6q

Reaction: Selective cleavage of Arg-|-Ser bond in complement component C3 alpha- chain to form C3a and C3b, and Arg-|-Xaa bond in complement component C5 alpha-chain to form C5a and C5b.
Other name(s): C3 convertase. C5 convertase. Complement C2.
Comments: A complex of complement fragments C4b, C2a and C2b. Belongs to peptidase family S1. Formerly Ec 3.4.21.44.
Links:   [IntEnz]   [ExPASy]   [KEGG]  

There are 5 PDB entries in enzyme class E.C.3.4.21.43

  PDB code Protein
2i6q
Complement component c2a
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: c2a. Expressed in: mesocricetus auratus. Expression_system_taxid: 10036.
Chain: A (503 residues) CATH domains: 3.40.50.410 2.40.10.10 2.40.10.10
2i6s
Complement component c2a
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: c2a. Expressed in: mesocricetus auratus. Expression_system_taxid: 10036.
Chain: A (497 residues) CATH domains: 3.40.50.410 2.40.10.10 2.40.10.10
2odp
Complement component c2a, the catalytic fragment of c3- and convertase of human complement
Source: Homo sapiens. Human. Organism_taxid: 9606. Expressed in: trichoplusia ni. Expression_system_taxid: 7111. Expression_system_cell_line: high five(bti-tn-5b1-4).
Chain: A (490 residues) CATH domains: 3.40.50.410 2.40.10.10 2.40.10.10
2odq
Complement component c2a, the catalytic fragment of c3- and convertase of human complement
Source: Homo sapiens. Human. Organism_taxid: 9606. Expressed in: trichoplusia ni. Expression_system_taxid: 7111. Expression_system_cell_line: high five(bti-tn-5b1-4).
Chain: A (492 residues) CATH domains: 3.40.50.410 2.40.10.10 2.40.10.10
3erb
The crystal structure of c2b, a fragment of complement component c2 produced during c3-convertase formation
Source: Homo sapiens. Human. Organism_taxid: 9606. Expressed in: trichoplusia ni. Expression_system_taxid: 7111. Expression_system_cell_line: high five(bti-tn-5b1-4).
Chain: A (188 residues) CATH domains: Unassigned 2.10.70.10 2.10.70.10