| Popis: |
Publisher Summary This chapter discusses the genetic determination of octopine degradation. Biochemical data on the tumor-specific lysopine synthesizing enzyme showed that a single enzyme accepted not only lysine as the amino acid substrate but also arginine, ornithine, and histidine. The bacterial permease for octopine is competitively inhibited by lysopine and octopinic acid. The same holds true for the octopine oxidase. The kinetics of competition for uptake was as would be expected if there were only one permease for all three mentioned opines. The first degradation products of octopine are pyruvate and arginine. Agrobacterium tumefaciens cells devoid of Ti plasmids can grow on arginine as a sole source of nitrogen. In addition to the chromosomally coded arginine catabolism pathway, an additional high efficiency system is coded for by the Ti plasmid. The second pathway only became evident in those chromosomal backgrounds that have a relatively inefficient chromosomal arginine degradation system. |
