p1. Four ribonucleases were isolated from culture media of iUstilago sphaerogena/i. They were designated ribonucleases Usub1/sub, Usub2/sub, Usub3/sub and Usub4/sub. 2. They were purified about 1600-, 3700-, 1100- and 16-fold respectively. 3. It was shown by gel filtration that ribonucleases Usub1/sub, Usub2/sub and Usub3/sub have molecular weights about 10000 like ribonuclease Tsub1/sub, and that ribonuclease Usub4/sub is much larger. 4. Ribonucleases Usub1/sub, Usub2/sub and Usub3/sub are thermostable, but ribonuclease Usub4/sub is not. 5. The pH optimum of ribonucleases Usub1/sub and Usub4/sub is pH8·0–8·5, and that of ribonucleases Usub2/sub and Usub3/sub is pH4·5./p
展开▼
