engine Protein Arrays are produced by combining contact printing technology with in situ protein expression directly on the PVDF-surface on which the screening assay will be performed. Recombinant protein expression in E.coli is the foundation for the further manufacturing process, followed by extraction and immobilization of expressed protein, on the PVDF membrane surface. Since the immobilization takes place under denaturating conditions, engine Protein Arrays consist mainly of almost linear sequence epitopes. These are ideally suited for epitope mapping, antibody cross-reactivity screening and for auto-antibody screenings. But since many proteins are not completely denaturated or do partially renature under assay conditions, engine Protein Arrays could also be used for the identification of DNA/RNA binding proteins or for functional assays, such as phosphorylation, methylation or ribosylation studies.