α-Crystallin protects glucose 6-phosphate dehydrogenase against inactivation by malondialdehyde

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE

卷:1500

Article

Ganea, E ; Harding, JJ

关键词: chaperone;    alpha-crystallin;    glucose 6-phosphate dehydrogenase;    lens;    malondialdehyde;   

DOI  :  10.1016/S0925-4439(99)00087-3

来源: Elsevier

【 摘 要 】

The present work investigates the effect of malondialdehyde (MDA) blinding on the enzymic activity and on some structural properties of glucose 6-phosphate dehydrogenase (G6PD). We studied whether alpha-crystallin could protect the enzyme against MDA damage, and if so, by what mechanism. We also studied whether alpha-crystallin could renature G6PD denatured by MDA. alpha-Crystallin was prepared from bovine lenses by gel chromatography. MDA was freshly prepared and incubated with G6PD with or without alpha-crystallin. The results show that MDA reacted with G6PD non-enzymically causing inactivation at concentrations lower than those used previously on structural proteins. The modified enzyme became fluorescent. alpha-Crystallin, acting as a molecular chaperone, specificality protected the enzyme against inactivation by MDA. The enzyme was not reactivated by alpha-crystallin, but it was stabilised and protected against further denaturation. Complex formation between alpha-crystallin and the modified enzyme was demonstrated by immunoprecipitation. G6PD was very susceptible to MDA and we have shown for the first time that alpha-crystallin is able to protect the enzyme against this damage. (C) 2000 Elsevier Science B.V. All rights reserved.

【 授权许可】

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