SECRETION OF CALF CHYMOSIN FROM THE FILAMENTOUS FUNGUS ASPERGILLUS-ORYZAE

Active calf chymosin was secreted from Aspergillus oryzae transformant s when the chymosin cDNA was expressed under the control of glucoamyla se gene (glaA) promoter. Secreted prochymosin was autocatalytically ac tivated to the chymosin (0.07-0.16 mg/l). Western blot analysis showed that a secreted protein immunoreactive with an anti-chymosin antibody was of similar size to authentic chymosin. Northern blot analysis rev ealed that mRNA of the chymosin cDNA was expressed at as high level as that of the glaA gene. The size and the level of the transcript were different among transformants, due to the integration position of the plasmid on the chromosome.