The present invention relates to immunoglobulin (Ig)-binding proteins with alkali-resistance properties. In one embodiment, the present invention provides for a variant of an Ig-binding protein, the variant comprising the Ig-binding protein having at least one asparagine residue substituted with a histidine, a serine, an aspartic acid or a threonine residue. The at least one substitution may confer to the variant Ig-binding protein an increased stability in alkaline solutions when compared to the wild-type Ig-binding. The present invention relates also to matrices for affinity separation of immunoglobulins comprising the Ig-binding proteins of the present invention, and to methods of using the Ig-binding proteins of the present invention to separate immunoglobulins from mixture compositions.