Figure 3.

Ribonucleolytic assay of wild‐type (WT) and mutant (MUT) R33W angiogenin (ANG) proteins. Enzyme activity was measured using yeast tRNA as substrate. Increasing concentrations (0.05–0.4 mg/ml) of WT and R33W (MUT) proteins were incubated with yeast tRNA (2 mg/ml) at 37°C for 2 hr. Undigested tRNA was precipitated with perchloric acid. The absorbance of the supernatants was measured at 260 nm. Data were collected from three independent measurements. Relative enzyme activity of the MUT ANG was calculated as compared with the WT protein (100%). The activity differences at concentrations 0.1, 0.2, 0.3, and 0.4 mg/ml were calculated