The NAD-linked aromatic α-hydroxy acid dehydrogenase fromTrypanosoma cruzi
| Autor: | Juan José Cazzulo, Cristina Nowicki, Javier Vernal, María C Cazzulo Franke |
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| Rok vydání: | 1999 |
| Předmět: |
Trypanosoma cruzi
Genes Protozoan Molecular Sequence Data Protozoan Proteins Dehydrogenase Biochemistry Isozyme Malate dehydrogenase Gene Expression Regulation Enzymologic chemistry.chemical_compound Cytosol Malate Dehydrogenase Escherichia coli Aromatic amino acids Animals Humans Citrate synthase Amino Acid Sequence DNA Primers chemistry.chemical_classification Base Sequence Sequence Homology Amino Acid biology Gene Expression Regulation Developmental Molecular biology Peptide Fragments Recombinant Proteins Alcohol Oxidoreductases Kinetics Enzyme chemistry biology.protein Oxoglutarate dehydrogenase complex Branched-chain alpha-keto acid dehydrogenase complex |
| Zdroj: | European Journal of Biochemistry. 266:903-910 |
| ISSN: | 0014-2956 |
| DOI: | 10.1046/j.1432-1327.1999.00926.x |
| Popis: | Trypanosoma cruzi, the protozoan parasite causing Chagas disease, contains a novel aromatic alpha-hydroxy acid dehydrogenase. This enzyme is responsible, together with tyrosine aminotransferase, for the catabolism of aromatic amino acids, which leads to the excretion of aromatic lactate derivatives into the culture medium. The gene encoding the aromatic alpha-hydroxy acid dehydrogenase has been cloned through a combined approach using screening of an expression genomic library with antibodies, peptide sequencing and PCR amplification. Its sequence shows high similarity to the cytosolic malate dehydrogenases. However, the enzyme has no malate dehydrogenase activity. The gene seems to be present in a single copy per haploid genome and is differentially expressed throughout the parasite's life cycle, the highest levels being found in the insect forms of T. cruzi. The purified recombinant enzyme, expressed in Escherichia coli, was unable to reduce oxaloacetate and had kinetic constants similar to those of the natural aromatic alpha-hydroxy acid dehydrogenase. Sequence comparisons suggest that the aromatic alpha-hydroxy acid dehydrogenase derives from a cytosolic malate dehydrogenase no longer present in the parasite, made redundant by the presence of a glycosomal malate dehydrogenase as a member of a shuttle device involving the mitochondrial isoenzyme. |
| Databáze: | OpenAIRE |
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