Investigation was carried out on different kinds of protein glues: restoration hide glue obtained from tanned calf leather and sturgeon glue. Parameters such as strength and maximum permissible deformation during mechanical testing of films were studied. Comparative analysis was carried out on properties of glues under investigation such as: appearance; development and subsequent relaxation of inner tensions springing up in glue joints when water evaporates in the course of the formation of a glue joint. These properties are of paramount significance in restoration practice. Investigation was also carried out on the properties of leukases prepared with different protein glue solutions. Molecular mass distribution of protein glues under investigation was determined on polyacrylamide gel plates by means of electrophoresis.