UBCH13 is a noncanonical ubiquitin conjugating enzyme (E2) that has been implicated in a variety of cellular signaling processes due to its ability to catalyze the formation of lysine 63-linked polyubiquitin chains on various substrates. In particular, UBCH13 is required for signaling by a variety of receptors important in immune regulation, making it a candidate target for inflammatory diseases. UBCH13 is also critical for double-strａnd DNA repair and thus a potential radiosensitizer and chemosensitizer target for oncology.The UBCH13 TR-FRET Assay Kit is designed to measure UBCH13 ubiquitination activity in a homogeneous 384 reaction format. It utilizes biotin-labeled ubiquitin and a terbium-labeled anti-His antibody to complete the TR-FRET pairing. This FRET-based assay requires no time-consuming washing steps, making it especially suitable for high throughput screening applications.