en Biotechnology Biotechnology Original Research Original Research <p><strong>Background: </strong>Betatrophin, a novel secretory protein from liver and fatty tissues, is believed to be involved in lipid and glucose metabolism. However, its precise physiological role remains unclear. Here, we report the cloning, expression, and purification steps of mouse betatrophin in a prokaryotic system, followed by its structural analysis.<br> <strong>&nbsp;&nbsp; Methods:</strong> Specific cloning primers were used to amplify the coding sequence of mouse liver betatrophin. The product was cloned into pET28 and expressed in E.coli BL21 (DE3) cells. The suitability of the refolding procedure was assessed by determining secondary structures of the initial and refolded proteins using circular dichroism spectroscopy.<br> <strong>&nbsp;&nbsp; Results: </strong>The polymerase chain reaction resulted in a 549 bp nucleotide sequence, encoding a 183 amino acid polypeptide, with an apparent molecular weight of 21 kDa, which was expressed in an inclusion body. Following an optimization and refolding procedure, the recombinant protein was purified by anion exchange and metal affinity chromatography. CD spectra revealed that the refolded protein has suitable configuration.<br> <strong>&nbsp;&nbsp; Conclusion:</strong> We believe that the produced betatrophin is suitable for further biochemical studies on glucose and lipid metabolism.<br> &nbsp;<br> &nbsp;</p> Mouse betatrophin, Recombinant protein, Refolding, CD spectroscopy, Chromatography 693 698 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-2201-1&slc_lang=en&sid=1 Samaneh Gholami Sama.gholami63@gmail.com 200319475328460034225 200319475328460034225 No Immunology Research Center, Iran University of Medical Sciences, Tehran, Iran. Koroush Goodarzvand Chegini Falak.r@iums.ac.ir kgchegini@qums.ac.ir 200319475328460034226 200319475328460034226 No Department of Biotechnology, Qazvin University of Medical Sciences, Qazvin, Iran. Nematollah Gheibi gheibi_n@yahoo.com 200319475328460034227 200319475328460034227 No Department of Biotechnology, Qazvin University of Medical Sciences, Qazvin, Iran. Kobra Mokhtarian K.mokhtarian@yahoo.com 200319475328460034228 200319475328460034228 No Immunology Research Center, Iran University of Medical Sciences, Tehran, Iran & Medical Plant Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran. Mohsen Mohamadi 200319475328460034229 200319475328460034229 No Immunology Research Center, Iran University of Medical Sciences, Tehran, Iran & The Persian Gulf Marine Biotechnology Medicine Research Center, Bushehr Universi-ty of Medical Sciences, Bushehr, Iran. Reza Falak Falak.r@iums.ac.ir 200319475328460034230 200319475328460034230 Yes Immunology Research Center, Iran University of Medical Sciences, Tehran, Iran & Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.