Studies on cow liver porphobilinogen deaminase
Further properties of cow liver deaminase are reported. Highly purified deaminase migrated as a single band on starch and polyacrylamide gels electrophoresis. Molecular weight determinations by means of gel filtration on calibrated columns of Sephadex G-100, Sepharose 4 B and B10-Gel P-100 gave valu...
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1976
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_NIS18664_v26_n5_p379_Sancovich http://hdl.handle.net/20.500.12110/paper_NIS18664_v26_n5_p379_Sancovich |
| Aporte de: |
| Sumario: | Further properties of cow liver deaminase are reported. Highly purified deaminase migrated as a single band on starch and polyacrylamide gels electrophoresis. Molecular weight determinations by means of gel filtration on calibrated columns of Sephadex G-100, Sepharose 4 B and B10-Gel P-100 gave values of 40,000 ± 4,000. Data obtained suggest that cow liver deaminase exists as a single polypeptide chain. Heating partially purified preparations of deaminase resulted in an enhancement of activity. Added cosynthetase to these fractions increased the percentage of uroporphyrinogen III formed but also diminished total uroporphyrinogens synthesis. The action of several compounds added to the system was studied. Thiol reagents and divalent metals as Hg2+, Pb2+, Cd2+ inhibited deaminase, indicating the presence of thiol groups essential for activity, probably involved in the cyclization step. Certain concentrations of sodium, potassium and magnesium salts enhanced activity. Several chelators tested were without effect on the deaminase. Some dicarboxylic acids and 2-methoxy-5-nitrotropone inhibited the enzyme. |
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