 The enzyme IdeS (Immunoglobulin degrading enzyme from "Streptococcus pyogenes", trade name FabRICATOR) cleaves IgG in a sequence specific manner at neutral pH.The F(ab')2 fragment can be split into two Fab' fragments by mild reduction.The variable regions of the heavy and light chains can be fused together to form a single-chain variable fragment (scFv), which is only half the size of the Fab fragment, yet retains the original specificity of the parent immunoglobulin.