Figure 6.

(A) Human recominant arginase prepared by Ikemoto et al (1990) was divided into two batches and compared with regard to inhibition of L1210 cells over two days, showing a dose-dependent effect similar to Figure 8 for HeLa cells. One of these batches was pegylated and compared with the other in terms of the breakdown of arginine to ornithine in the next figure. (B) Alterations in the levels of arginine and ornithine in RPMI medium measured in the amino-acid analyser after incubation for 5 and 10 min, to show their relative rates of arginine loss in unpegylated (▪) and (□) pegylated enzyme, and correspondingly the rise in ornithine in unpegylated (•) and pegylated (○) arginase treatment set at precisely 1 unit ml⁻¹ of the original preparation in both cases.