This book is attempt to clarify some structural and functional protein disfunctions that are related with molecular pathologies. These consist of a wide group of diseases, which are induced by the disruption of the normal physiological processes because of the inability of some proteins to take part into inter-molecular interactions mediating these processes. It presents materials concerning autoimmune, folding and genetic pathologies, problems of the ensuring of functional activity of the protein preparations and biocompatibility of medical implants.