The invention discloses an optimized cattle
chymosin proto-
gene and a secretory expression method and the application thereof. According to the optimized cattle
chymosin proto-
gene, influence factors of difference between
protein interpret rates and the like due to use frequency of codon, adjustment of
GC content, deletion of unstable sequences, and different distribution of secondary mRNA structure and the codon are comprehensively considered, and optimized cattle
chymosin proto-
gene bodies respectively shown by SEQ ID NO.1, 2 and 3 are obtained by modifying cattle chymosin proto-gene bodies according to the preference codon of
pichia pastoris. The invention further provides a production method of recombining the cattle chymosin proto-gene. The production method comprises the steps of converting
recombinant expression carriers containing the optimized cattle chymosin proto-gene bodies into host cells to obtain recombination bacterial strains, cultivating the recombination bacterial strains, inducing expression of the recombination cattle chymosin proto-gene bodies, and recycling and purifying expressed products. Compared with original cattle chymosin proto-gene, the secretory expression amount and the
enzyme activity of the optimized cattle chymosin proto-gene in the
pichia pastoris are remarkably promoted.