7863-2004 recognises protein gene product 9.5 (PGP9.5), a ubiquitin hydrolase which is widely expressed in neuronal tissues and represents 1-2% of total soluble brain proteins. PGP9.5, also known as ubiquitin C-terminal hydrolase 1 (UCHL-1), is involved in the regulation of the ubuiquitin pathway. This product stains neuronal cell bodies and axons in the CNS and periphery, small nerve fibres in peripheral tissues, neuroendocrine cells in the pituitary, thyroid, pancreas and tumours of the DNES. Also stains neuroendocrine cells in human adult gut (unlike 31A3). Clones 31A3 and 13C4 each recognise a different epitope towards the N-terminus of the protein.