UBL4A, also known as GDX, contains 1 ubiquitin-like domain. Post-translational modification by ubiquitin and ubiquitin-related proteins plays critical roles in protein degradation and in regulation of essential cellular processes. In mammals, transcription grinds to a halt during late spermiogenesis due to compaction of the spermatid genome, which creates a special need for robust post-transcriptional regulation. UBL4A plays any role in targeting cellular proteins for degradation. Recombinant human UBL4A protein, fused to His-tag at C-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.