abstract |
NEW MATERIAL:The growth hormone polypeptide for fish, having the peptide sequence of formula. USE:Fish-growth promoting agent for pisciculture. PREPARATION:For example, the pituitary gland of Oncorhynchus keta is disinte grated and solubilized in a solution containing guanidium thiocyanate, and added to an EDTA solution. The mixture is centrifuged to recover the LRNA as a precipitate, which is dissolved in a concentrated solution of NaCl, etc., and passed through a column of oligo(dT)cellulose to obtain an mRNA having poly(A). A cyclic cDNA is synthesized from the mRNA, a vector primer and a linker DNA, and Escherichia coli is transformed with the cDNA to obtain a mutant containing a recombinant DNA integrated with a DNA coding the fish growth hormone. The mutant is cultured in a nutrient medium to obtain the objective polypeptide having the structure of formula. |