PURPOSE: A conjugated plasmid that contains cDNA of calf prorennin and is used to produce prorennin, which is the precursor of rennin, a milk coagulation enzyme that is essential for cheese production, by utilizing the gene recombination technology.
CONSTITUTION: Prorennin mRNA is extracted from mucous membranes of calf 4-th stomach and the mRNA is used as a template to synthesize a complemetary single-stranded DNA by used of a reverse transcriptase. After the template mRNA is removed, DNA polymerase I is used to synthesize a complementary duplex DNA, then its hair-pin structure part is selectively removed to give a prorennin cDNA with completely duplex structure. For example, poly-dG-homopolymer is added to both 3' terminals of the cDNA and the product is mixed with a linear pBR322 DNA made by adding poly-dC-homopolymer to 3' terminals to prepare a conjugated plasmid containing calf prorennin cDNA.
UOZUMI TAKESHI
NISHIMORI KATSUHIKO
