| 摘要 |
<p>PURPOSE:To prepare the subject gene in high purity and efficiency by culturing a transformant containing a specific DNA fragment in a selenium-containing medium. CONSTITUTION:A phage vector is integrated in an mRNA prepared from a human placenta tissue and the obtained library is screened to obtain a DNA fragment composed of a subunit having a molecular weight of 23,000+ or -2,000, exhibiting a glutathione peroxidase activity catalyzing the reaction to form 2mol of glutathione oxide and 2 mol of H2O from 2mol of glutathione and 1mol of H2O2 and containing a base sequence coding a polypeptide consisting of human plasma-type glutathione peroxidase and containing the amino acid sequence of formula I (*** is selenocysteine residue) near the active center, the amino acid sequence of formula II at the N-terminal side and the amino acid sequence of formula III at the C-terminal side. The fragment is introduced into an animal cell, etc., and the obtained transformant is cultured in a selenium- containing medium. The cultured product is extracted and purified to obtain a polypeptide constituting the peroxidase.</p> |
