URM1 is ubiquitin-related modifier 1 homolog protein that primarily functions in the post-translational modification of proteins by way of the urmylation pathway. In studies with Saccharomyces cerevisiae, it has been found that Urm1 covalently binds to its E1 activating enzyme, Uba4p, to conjugate alkyl hydroperoxide reductase (Ahp1). It is hypothesized that this complex may then play a role in the oxidative-stress response in mammals. Recombinant human URM1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.