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Purification and properties of a neutral protease from calf thymus nuclei

1968; Elsevier BV; Volume: 167; Issue: 1 Linguagem: Inglês

10.1016/0005-2744(68)90285-4

1878-1454

Miha Furlan, Marija Jericijo, A. Suhar,

Blood Coagulation and Thrombosis Mechanisms

1. A neutral protease has been purified from calf thymus nuclei by extraction with 2.5 M NaCl, ethanol fractionation, gel filtration on Sephadex G-75 and incubation at the pH optimum. 2. The pH optimum for deoxyribonucleohistone hydrolysis is 7.8. Hemoglobin, serum albumin and γ-globulin were considerably more resistant to digestion than deoxyribonucleohistone. Hydrolytic degradation of hemoglobin was inhibited by substrate concentrations above 0.5%. 3. The protease is heat labile; its activity was almost completely abolished after heating for 20 in at 60°. The pH stability was studied at 37° and the enzyme was found to be stable over the pH range 5–9. The activity was rapidly lost below pH 3.5. The protease was slightly inhibited by Cd2+ and Co2+, and markedly by p-chloromercuribenzoate and diisopropyl fluorophosphate. Other metal ions, EDTA, cyanide, cysteine and iodoacetamide had no effect.