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IgG subclasses

IgG subclasses IgG1 IgG2 IgG3
Molecular weight of secreted form (kDa) (1) 170 100 100
Chain composition L2γ12 γ22 γ32

IG chain characteristics

IG chain types L γ1 γ2 γ3
Molecular weight (kDa) 30 50 46 43
Number of variable domains 1 1 1 1
Number of constant domains 1 3 2 (5) 2 (5)
Binding to protein A - + + +
Binding to protein G - + 0 +
Hinge (2) - 11 35 12
Membrane IG transmembrane region (2) - 25
Membrane IG intracytoplasmic region (2) - 28
Secreted IG tailpiece (2)(3) - 2 2
N-glycosylation sites (4) 2 1

L: Light chain

IMGT notes:
(1) Approximate molecular weight.
(2) Length in number of amino acids. The gamma1 hinge length is from llama (Lama glama) (AF305955)
(3) Encoded by CHS.
(4) N-glycosylation sites (NXS/T, where X is different from P).
(5) No CH1 domain due to an absence of splicing of the CH1 exon [1].
References:
[1] Nguyen, K.V. et al., Mol. Immunol., 36, 515-524 (1999).
[2] Atarhouch, T. et al., unpublished.
[3] Nguyen, K.V. et al., Immunogenetics, 54, 39-47 (2002)