Description_x000D_ General description_x000D_ Jo-1, or histidyl-transfer ribonucleic acid synthetase, is a homodimeric enzyme that catalyzes the coupling of histidine to its specific transfer RNA (tRNA), prior to transport of histidine to the ribosome, and subsequent incorporation of histidine into polypeptide chains. Jo-1 has been associated with various autoimmune disorders, such as polymyositis and dermatomyositis, and T-cell mediated autoimmunity._x000D_ Biochem/physiol Actions_x000D_ The anti-Jo-1 antibody has been associated with an increased frequency of interstitial pulmonary disease in polymyositis/dermatomyositis patients._x000D_ Used in the immunoassay for antibodies to Jo-1._x000D_ Physical form_x000D_ Solution in 6 M urea, 500 mM sodium chloride, 10 mM Tris HCl buffer, pH 8.0.