Anenzyme expressed by Streptococcus pyogenes capable of releasing the
terminal sialic acid residues from glycoproteins such as immunoglobulins.Specifically catalyzes the hydrolysis of the beta-1,4 linkage between
the first two N-acetylglucosamine residues of the complex-type N-linked glycan
located on 'Asn-297' of the Fc region of IgG antibodies （IGHG1, IGHG2, IGHG3 or
IGHG4）, thereby preventing interaction between IgGs and Fc receptors and
ability to activate the complement pathway. Endo S is an endoglycosidase
specific for cleaving the N-linked glycans from the chitobiose core of the
heavy chain of native IgG.