Cloning of the K. fragilis PDI Gene

The K. fragilis CBS 397 gene library was screened by the PDI probe, which was designed according to the homology with the S. cerevisiae PDI gene. One positive clone was found and confirmed. In order to learn its physical map, Southern hybridization was done on this positive clone. The K. fragilis PDI gene was found to locate in chromosome Ⅴ genome. Its sequence was also made partly known by DNA sequencing. From the method of the turbidimetric assay of insulin disulfide reduction, we have also demonstrated that the cloned PDI gene can exhibit PDI activity.