How does hexachlorobenzene treatment affect liver uroporphyrinogen decarboxylase?
The aims of the present work were: (1) to investigate whether the strong decrease of liver uroporphyrinogen decarboxylase (UroD) activity observed in experimental porphyria cutanea tarda is due to alteration of the enzymatic protein and (2) to improve the knowledge about the normal liver enzyme. Wit...
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2001
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_13572725_v33_n6_p621_Chaufan http://hdl.handle.net/20.500.12110/paper_13572725_v33_n6_p621_Chaufan |
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paper:paper_13572725_v33_n6_p621_Chaufan2023-06-08T16:11:16Z How does hexachlorobenzene treatment affect liver uroporphyrinogen decarboxylase? Active site Antigenic determinants Hexachlorobenzene Porphyria cutanea tarda Uroporphyrinogen decarboxylase cadmium copper ion cystine dithiothreitol glutathione hexachlorobenzene lead liver enzyme mercaptoethanol mercury uroporphyrinogen decarboxylase zinc ion animal experiment animal model antigenicity article atom concentration response controlled study drug activity enzyme activity enzyme analysis enzyme binding enzyme conformation enzyme inhibition hydration nonhuman pH physical chemistry porphyria cutanea tarda rat Animals Antigens Female Fungicides, Industrial Hexachlorobenzene Hydrogen-Ion Concentration Liver Rats Rats, Wistar Temperature Uroporphyrinogen Decarboxylase The aims of the present work were: (1) to investigate whether the strong decrease of liver uroporphyrinogen decarboxylase (UroD) activity observed in experimental porphyria cutanea tarda is due to alteration of the enzymatic protein and (2) to improve the knowledge about the normal liver enzyme. With these purposes, several physicochemical studies for enzymatic characterization were carried out comparatively on the 12-fold purified liver enzyme of both normal and hexachlorobenzene porphyric rat. The study shows that the enzyme from porphyric rats has a higher activation energy, lower reactivity index and lower optimum pH than the normal one. In addition, it did not reach the Vmax at any of the substrate concentrations assayed (up to 28 μM uroporphyrinogen III), while the normal enzyme reached the plateau around 14 μM. The porphyric enzyme appears to be more protected than the normal against the inhibitory action of several metals, particularly Cu2+ and Pb2+, and against thermal inactivation. Zn2+ did not affect enzymatic activity, whereas Cu2+, Hg2+, Fe2+, Pb2+, and Cd2+ lowered the activities of both normal and porphyric enzyme in a dose-related way. It was also observed that the larger the atomic radius in its hydrated state, the lower the effect of the metal. Neither glutathione nor dithiothreitol significantly altered enzymatic activity in the range of concentrations assayed. β-Mercaptoethanol had diverse effects, as regards both the concentration assayed and the enzymatic sample used. Assays with cystine showed a dual behaviour of both normal and porphyric enzymatic activity. Western blots for both preparations revealed a single band (65 kDa) with a similar intensity. This study show that hexachlorobenzene treatment modifies the physicochemical properties of liver UroD leading to a sharp decrease of its activity, without affecting its antigenic reactivity probably as a consequence of changes at the conformational level promoted by the binding of its reported inhibitor. © 2001 Elsevier Science Ltd. 2001 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_13572725_v33_n6_p621_Chaufan http://hdl.handle.net/20.500.12110/paper_13572725_v33_n6_p621_Chaufan |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Active site Antigenic determinants Hexachlorobenzene Porphyria cutanea tarda Uroporphyrinogen decarboxylase cadmium copper ion cystine dithiothreitol glutathione hexachlorobenzene lead liver enzyme mercaptoethanol mercury uroporphyrinogen decarboxylase zinc ion animal experiment animal model antigenicity article atom concentration response controlled study drug activity enzyme activity enzyme analysis enzyme binding enzyme conformation enzyme inhibition hydration nonhuman pH physical chemistry porphyria cutanea tarda rat Animals Antigens Female Fungicides, Industrial Hexachlorobenzene Hydrogen-Ion Concentration Liver Rats Rats, Wistar Temperature Uroporphyrinogen Decarboxylase |
| spellingShingle |
Active site Antigenic determinants Hexachlorobenzene Porphyria cutanea tarda Uroporphyrinogen decarboxylase cadmium copper ion cystine dithiothreitol glutathione hexachlorobenzene lead liver enzyme mercaptoethanol mercury uroporphyrinogen decarboxylase zinc ion animal experiment animal model antigenicity article atom concentration response controlled study drug activity enzyme activity enzyme analysis enzyme binding enzyme conformation enzyme inhibition hydration nonhuman pH physical chemistry porphyria cutanea tarda rat Animals Antigens Female Fungicides, Industrial Hexachlorobenzene Hydrogen-Ion Concentration Liver Rats Rats, Wistar Temperature Uroporphyrinogen Decarboxylase How does hexachlorobenzene treatment affect liver uroporphyrinogen decarboxylase? |
| topic_facet |
Active site Antigenic determinants Hexachlorobenzene Porphyria cutanea tarda Uroporphyrinogen decarboxylase cadmium copper ion cystine dithiothreitol glutathione hexachlorobenzene lead liver enzyme mercaptoethanol mercury uroporphyrinogen decarboxylase zinc ion animal experiment animal model antigenicity article atom concentration response controlled study drug activity enzyme activity enzyme analysis enzyme binding enzyme conformation enzyme inhibition hydration nonhuman pH physical chemistry porphyria cutanea tarda rat Animals Antigens Female Fungicides, Industrial Hexachlorobenzene Hydrogen-Ion Concentration Liver Rats Rats, Wistar Temperature Uroporphyrinogen Decarboxylase |
| description |
The aims of the present work were: (1) to investigate whether the strong decrease of liver uroporphyrinogen decarboxylase (UroD) activity observed in experimental porphyria cutanea tarda is due to alteration of the enzymatic protein and (2) to improve the knowledge about the normal liver enzyme. With these purposes, several physicochemical studies for enzymatic characterization were carried out comparatively on the 12-fold purified liver enzyme of both normal and hexachlorobenzene porphyric rat. The study shows that the enzyme from porphyric rats has a higher activation energy, lower reactivity index and lower optimum pH than the normal one. In addition, it did not reach the Vmax at any of the substrate concentrations assayed (up to 28 μM uroporphyrinogen III), while the normal enzyme reached the plateau around 14 μM. The porphyric enzyme appears to be more protected than the normal against the inhibitory action of several metals, particularly Cu2+ and Pb2+, and against thermal inactivation. Zn2+ did not affect enzymatic activity, whereas Cu2+, Hg2+, Fe2+, Pb2+, and Cd2+ lowered the activities of both normal and porphyric enzyme in a dose-related way. It was also observed that the larger the atomic radius in its hydrated state, the lower the effect of the metal. Neither glutathione nor dithiothreitol significantly altered enzymatic activity in the range of concentrations assayed. β-Mercaptoethanol had diverse effects, as regards both the concentration assayed and the enzymatic sample used. Assays with cystine showed a dual behaviour of both normal and porphyric enzymatic activity. Western blots for both preparations revealed a single band (65 kDa) with a similar intensity. This study show that hexachlorobenzene treatment modifies the physicochemical properties of liver UroD leading to a sharp decrease of its activity, without affecting its antigenic reactivity probably as a consequence of changes at the conformational level promoted by the binding of its reported inhibitor. © 2001 Elsevier Science Ltd. |
| title |
How does hexachlorobenzene treatment affect liver uroporphyrinogen decarboxylase? |
| title_short |
How does hexachlorobenzene treatment affect liver uroporphyrinogen decarboxylase? |
| title_full |
How does hexachlorobenzene treatment affect liver uroporphyrinogen decarboxylase? |
| title_fullStr |
How does hexachlorobenzene treatment affect liver uroporphyrinogen decarboxylase? |
| title_full_unstemmed |
How does hexachlorobenzene treatment affect liver uroporphyrinogen decarboxylase? |
| title_sort |
how does hexachlorobenzene treatment affect liver uroporphyrinogen decarboxylase? |
| publishDate |
2001 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_13572725_v33_n6_p621_Chaufan http://hdl.handle.net/20.500.12110/paper_13572725_v33_n6_p621_Chaufan |
| _version_ |
1768545019573043200 |