The Spot-System is the first peptide-tag specific Nanobody for capture & detection. It combines the advantages of both Spot-Nanobody and Spot-Tag. The Spot-Tag has an affinity-optimized 12 amino acid sequence to be strongly bind to the Spot-Nanobody. It it possible to attach the tag N-terminal or C-terminal to the protein of interest either by PCR or using modified primers or by using a specialised Spot vector. Bacteria, yeast, mammalian cell lines, and insect cells have already successfully been tested as expression system for Spot-tagged proteins.