Recombinant Human DIO2 protein

**Background of DIO2 Recombinant Protein**

Deiodinase iodothyronine type 2 (DIO2) is a selenocysteine-containing enzyme critical in regulating thyroid hormone metabolism. It catalyzes the outer-ring deiodination of the prohormone thyroxine (T4) to bioactive triiodothyronine (T3), a key regulator of energy homeostasis, growth, and development. DIO2 is primarily expressed in tissues such as the brain, pituitary, thyroid, and brown adipose tissue, playing a pivotal role in local T3 availability and adaptive thermogenesis.

Recombinant DIO2 protein is engineered using molecular cloning techniques, often expressed in prokaryotic (e.g., *E. coli*) or eukaryotic systems (e.g., mammalian cells) to preserve enzymatic activity. Its production enables detailed study of DIO2 structure-function relationships, substrate specificity, and regulatory mechanisms (e.g., post-translational modifications, ubiquitination). Researchers utilize recombinant DIO2 to investigate thyroid-related disorders, including hypothyroidism, resistance to thyroid hormone (RTH), and metabolic syndromes linked to altered T3 signaling.

DIO2 dysfunction is implicated in conditions like metabolic obesity, neurodevelopmental defects, and mood disorders, making its recombinant form valuable for drug screening and therapeutic targeting. Studies also explore DIO2's role in adaptive responses to cold, fasting, and illness, where localized T3 production modulates tissue-specific metabolic demands.

The recombinant protein typically includes affinity tags (e.g., His-tag) for purification and detection. Activity assays often measure iodine release from T4 or T3 generation via spectrophotometric/radioactive methods. Challenges in production include maintaining selenocysteine incorporation (critical for catalytic activity) and avoiding oxidative inactivation.

Overall, recombinant DIO2 serves as a vital tool for dissecting thyroid hormone dynamics, developing diagnostic assays, and exploring therapeutic interventions for endocrine and metabolic diseases.