DBR1 is an RNA lariat debranching enzyme that hydrolyzes 2'-5' prime branched phosphodiester bonds. The encoded protein specifically targets the bonds at the branch point of excised lariat intron RNA, converting them to linear molecules that are then degraded. This protein may also be involved in retroviral replication. Recombinant human DBR1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.