| 摘要 |
NEW MATERIAL:A compound having the peptide sequence of the formula. USE:A growth promotor for fish. PREPARATION:For example, hypophysis is extracted from white salmons, frozen, crushed for solubilization, and ultracentrifuged to collect RNA as a precipitate. The RNA is dissolved in a high-concentration salt solution of NaCl or the like, and passed through an oligo(dT)cellulose column to obtained poly(A)RNA. The product is allowed to bond to a suitable vector primer, a reverse transcriptase is allowed to act on to prepare cDNA, which is cyclized by reaction in the presence of a suitable linker DNA and an enzyme. Further, the cyclized DNA is allowed to react with a nucleoside in the presence of an enzyme to form a recombined plasmid containing double-stranded cDNA. Then, the cDNA is introduced into Escherishia coil to effect transformation. Finally the microorganism is cultured to obtain prolactin polypeptide in fish. |
