Mitochondrial branched chain aminotransferase gene expression in AS-30D hepatoma rat cells and during liver regeneration after partial hepatectomy in rat
| Autor: | Rogelio Hernández-Pando, Ana H. Moranchel, Susan M. Hutson, Armando R. Tovar, Graciela Pérez-Villaseñor, Nimbe Torres |
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| Rok vydání: | 2005 |
| Předmět: |
Branched chain aminotransferase
Blotting Western Mitochondria Liver Biology Isozyme Gene Expression Regulation Enzymologic General Biochemistry Genetics and Molecular Biology Liver Neoplasms Experimental Valine Cell Line Tumor Animals Hepatectomy Rats Wistar General Pharmacology Toxicology and Pharmaceutics Transaminases Catabolism General Medicine Blotting Northern Immunohistochemistry Molecular biology Liver regeneration Liver Regeneration Rats Isoenzymes Blot Biochemistry Hepatocytes Female Leucine Isoleucine Amino Acids Branched-Chain Neoplasm Transplantation |
| Zdroj: | Life Sciences. 78:334-339 |
| ISSN: | 0024-3205 |
| DOI: | 10.1016/j.lfs.2005.04.079 |
| Popis: | Branched chain aminotransferase (BCAT) is the first enzyme in the catabolism of branched chain amino acids (BCAA). Unlike other amino acid degrading enzymes present in liver, BCAT is only expressed in extrahepatic tissues, and is not regulated by dietary protein, glucagon or glucocorticoids. However, the mitochondrial (m) isoform of BCAT is highly expressed in the fetal liver and rapidly decays after birth. The purpose of the present work was to establish if liver cells under conditions of rapid cell proliferation such as in hepatoma AS30D cells or during liver regeneration after partial hepatectomy were associated with an increase in the activity and expression of BCATm. BCAT activity in mitochondria of AS30D cells was 18.6 mU/mg protein. Western, Northern blot, and immunohistochemical analysis revealed that AS30D hepatoma cells expressed only BCATm. The apparent Km of BCATm in isolated AS30D cells mitochondria for leucine, isoleucine and valine was 1.0+/-0.02, 1.3+/-0.1 and 2.1+/-0.1 mM, respectively. The regenerated liver showed BCAT activity from day 3 to day 6, and the maximal BCAT activity (7.0 mU/mg protein) was on day 5. By day 14 after partial hepatectomy BCAT activity and expression was almost undetectable. Interestingly, there was a relationship between BCAT activity and the Mr. of the immunoreactive band of BCATm. The presence of a 41 kDa band was associated with BCAT activity, whereas the 43 kDa band with undetectable activity. The results of this study indicate that BCATm activity is required in liver cells under conditions of rapid cell proliferation. |
| Databáze: | OpenAIRE |
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