FIGURE 5.

Genetic and enzymatic analysis of OPB knockouts. A, successful deletion of both genomic copies of the OPB gene were determined by Southern blot analysis. Digested genomic DNA from wild type, single copy, and double copy knockouts were analyzed at the OPB locus for the presence of either the wild type locus or the knock-out cassette. The blot was stripped and reprobed for the OPB gene itself to ensure that the gene was not relocated to another site in the genome. B, lysates from wild type, single copy, and double copy knockouts were analyzed for OPB enzymatic activity using the Z-PR-AMC substrate at pH 8.0.