Effect of Proteinase A Propeptide Deletion on its Enzyme Activity in Saccharomyces cerevisiae

摘要

Two expression plasmids YCP-EP and YCP-54A respectively expressing the complete PEP4 gene and the incomplete PEP4 gene without the prosequence (encode the propeptide of proteinase A) from Saccharomyces cerevisiae W303-1A were constructed and transferred into S. cerevisiae W303-K22 (ΔPEP4). The yeast transformants WYCP-EP and WYCP-54A were obtained. Meanwhile, a mutant strain W54A deleted the prosequence of PEP4 was obtained by homologous recombination. The proteinase A enzyme activities of the yeast transformants WYCP-EP, WYCP-54A and the mutant strain W54A were detected by fluorescent substrate, respectively. The results showed that only the strain WYCP-EP was able to produce the active proteinase A. Consequently, the results confirmed that the propeptide was required for formation of active mature proteinase A, and it provided the theoretical basis for the construction of genetic engineering strain with low-proteinase A by the deletion of prosequence.