The use of an indirect Enzyme-Linked Immunosorbent Assay (ELISA) method for the identification, down to a species level, of proteinaceous binding media and adhesives in works of art is presented. The production and application of a custom-made specific antibody to sturgeon glue is described and challenges of species specificity, detection limits, as well as localization of the protein in the sample stratigraphy are discussed through results obtained from analysis of replica and artwork samples. The custom-made antibody has proven highly specific to sturgeon species only and is suitable for the identification of sturgeon glue in works of art. ELISA screening for ovalbumin, casein, and collagen (unspecific) demonstrates the identification of proteins even in mixtures.