Structural and enzymatic properties of mammalian d-glutamate cyclase.
Arch Biochem Biophys
; 654: 10-18, 2018 09 15.
Article
en En
| MEDLINE
| ID: mdl-30003876
ABSTRACT
d-Glutamate cyclase (DGLUCY) is a unique enzyme that reversibly converts free d-glutamate to 5-oxo-d-proline and H2O. Mammalian DGLUCY is highly expressed in the mitochondrial matrix in the heart, and its downregulation disrupts d-glutamate and/or 5-oxo-d-proline levels, contributing to the onset and/or exacerbation of heart failure. However, detailed characterisation of DGLUCY has not yet been performed. Herein, the structural and enzymatic properties of purified recombinant mouse DGLUCY were examined. The results revealed a dimeric oligomerisation state, and both d-glutamate-to-5-oxo-d-proline and 5-oxo-d-proline-to-d-glutamate reactions were catalysed in a stereospecific manner. Catalytic activity is modulated by divalent cations and nucleotides including ATP and ADP. Interestingly, the presence of Mn2+ completely abolished the 5-oxo-d-proline-to-d-glutamate reaction but stimulated the d-glutamate-to-5-oxo-d-proline reaction. The optimum pH is â¼8.0, similar to that in the mitochondrial matrix, and the catalytic efficiency for d-glutamate is markedly higher than that for 5-oxo-d-proline. These findings suggest that DGLUCY functions as a metalloenzyme that degrades d-glutamate in the mitochondrial matrix in mammalian cells. The results also provide insight into the correlation between DGLUCY enzyme activity and the physiological and pathological roles of d-glutamate and 5-oxo-d-proline in cardiac function, which is of relevance to the risk of onset of heart failure.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Hidroliasas
Límite:
Animals
Idioma:
En
Revista:
Arch Biochem Biophys
Año:
2018
Tipo del documento:
Article
País de afiliación:
Japón