Acetylornithine aminotransferase TM1785 performs multiple functions in the hyperthermophile Thermotoga maritima
| Autor: | Masae Sekine, Kumiko Sakai-Kato, Yasuaki Saitoh, Masumi Katane, Hiroshi Homma, Tetsuya Miyamoto |
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| Rok vydání: | 2021 |
| Předmět: |
Ornithine
Biophysics Glutamic Acid Biochemistry Substrate Specificity chemistry.chemical_compound Bacterial Proteins Biosynthesis Structural Biology Enzyme Stability Serine Genetics Thermotoga maritima Cysteine Amino-acid racemase Lyase activity Molecular Biology Transaminases Cysteine lyase Lysine racemase biology Chemistry Threonine Dehydratase Cell Biology biology.organism_classification Kinetics Dehydratase bacteria |
| Zdroj: | FEBS Letters. 595:2931-2941 |
| ISSN: | 1873-3468 0014-5793 |
| DOI: | 10.1002/1873-3468.14222 |
| Popis: | The hyperthermophilic bacterium Thermotoga maritima peptidoglycan contains unusual d-lysine alongside typical d-alanine and d-glutamate. We previously identified lysine racemase and threonine dehydratase, but knowledge of d-amino acid metabolism remains limited. Herein, we identified and characterized T. maritima acetylornithine aminotransferase TM1785. The enzyme was most active towards acetyl-l-ornithine, but also utilized l-glutamate, l-ornithine and acetyl-l-lysine as amino donors, and 2-oxoglutarate was the preferred amino acceptor. TM1785 also displayed racemase activity towards four amino acids and lyase activity towards l-cysteine, but no dehydratase activity towards l-serine, l-threonine or corresponding d-amino acids. Catalytic efficiency (kcat /Km ) was highest for aminotransferase activity and lowest for racemase activity. TM1785 is a novel acetylornithine aminotransferase associated with l-arginine biosynthesis that possesses two additional distinct activities. |
| Databáze: | OpenAIRE |
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