Linkage specific phosphorylated Poly-Ubiquitin chains may be used as a substrate for in vitro reactions with deubiquitinating enzymes ("DUB's") that cleave the peptide or isopeptide linkage between adjacent Ubiquitin molecules. Phosphorylated Poly-Ubiquitin chains can also be used to investigate mechanisms of binding and recognition between the chains and other proteins that contain Ubiquitin-Associated domains (UBAs), Ubiquitin-interacting motifs (UIMs), ZnF's and/or other Ubiquitin-sensing elements.
Linear (Met1-linked) Tetra-Ubiquitin chains phosphorylated at Serine 65 are manufactured using recombinant wild-type human recombinant Ubiquitin and PINK1 kinase. The use of purely enzymatic techniques avoids the potential for contaminating synthetic intermediates. The purity of each production lot is assessed using the Absolute Quantitation of Ubiquitin method (Ub-AQUA), an LCMS-based technique that provides extremely accurate information on the composition of Poly-Ubiquitin samples.