Structure/function analysis of a critical disulfide bond in the active site of L-xylulose reductase.
Cell Mol Life Sci
; 66(9): 1570-9, 2009 May.
Article
em En
| MEDLINE
| ID: mdl-19337691
ABSTRACT
L-xylulose reductase (XR) is involved in water re-absorption and cellular osmoregulation. The crystal structure of human XR complemented with site-directed mutagenesis (Cys138Ala) indicated that the disulfide bond in the active site between Cys138 and Cys150 is unstable and may affect the reactivity of the enzyme. The effects of reducing agents on the activities of the wild-type and mutant enzymes indicated the reversibility of disulfide-bond formation, which resulted in three-fold decrease in catalytic efficiency. Furthermore, the addition of cysteine (>2 mM) inactivated human XR and was accompanied by a 10-fold decrease in catalytic efficiency. TOF-MS analysis of the inactivated enzyme showed the S-cysteinylation of Cys138 in the wild-type and Cys150 in the mutant enzymes. Thus, the action of human XR may be regulated by cellular redox conditions through reversible disulfide-bond formation and by S-cysteinylation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Desidrogenase do Álcool de Açúcar
Limite:
Humans
Idioma:
En
Revista:
Cell Mol Life Sci
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Austrália