Homocysteine-responsive endoplasmic reticulum-resident ubiquitin-like domain member 1 protein, also known as HERPUD1, is a 391 amino acid multi-pass membrane protein that localizes to the ER and contains one N-terminal ubiquitin-like domain. Widely expressed with highest expression in the brain, HERP is a component of the ERAD system and, via its ubiquitin-like domain, is thought to be involved in the destruction of misfolded proteins. Recombinant human HERPUD1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.