Thiol/Disulfide Interconversion in Bovine Lens Aldose Reductase Induced by Intermediates of Glutathione Turnover
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- 作者：Pier Giuseppe Vilardo ; Andrea Scaloni ; Pietro Amodeo ; Catia Barsotti ; Ilaria Cecconi ; Mario Cappiello ; Blanca Lopez Mendez ; Rosario Rullo ; Massimo Dal Monte ; Antonella Del Corso ; and Umberto Mura
- 刊名：Biochemistry
- 出版年：2001
- 出版时间：October 9, 2001
- 年：2001
- 卷：40
- 期：40
- 页码：11985 - 11994
- 全文大小：366K
- 年卷期：v.40,no.40(October 9, 2001)
- ISSN：1520-4995
文摘
The effectiveness of cysteine and cysteinylglycine to act as protein thiolating agents wasinvestigated using bovine lens aldose reductase (ALR2) as the protein target. Disulfides of both thiolcompounds appear to be very effective as ALR2 thiolating agents. Cysteine- and CysGly-modified ALR2forms (Cys-ALR2 and CysGly-ALR2, respectively) are characterized by the presence of a mixed disulfidebond involving Cys298, as demonstrated by a combined electrospray mass spectrometry and Edmandegradation approach. Both Cys-ALR2 and CysGly-ALR2 essentially retain the ability to reduceglyceraldehyde but lose the susceptibility to inhibition by Sorbinil and other ALR2 inhibitors. Cys-ALR2and CysGly-ALR2 are easily reduced back to the native enzyme form by dithiothreitol and GSH treatment;on the contrary, Cys and 2-mercaptoethanol appear to act as protein trans-thiolating agents, rather thanreducing agents. The treatment at 37 
C of both Cys-ALR2 and CysGly-ALR2, unlikely what observedfor glutathionyl-modified ALR2 (GS-ALR2), promotes the generation of an intramolecular disulfide bondbetween Cys298 and Cys303 residues. A rationale for the special susceptibility of Cys-ALR2 and CysGly-ALR2, as compared to GS-ALR2, to the thermally induced intramolecular rearrangement is given on thebasis of a molecular dynamic and energy minimization approach. A pathway of thiol/disulfideinterconversion for bovine lens ALR2 induced, in oxidative conditions, by physiological thiol compoundsis proposed.
C of both Cys-ALR2 and CysGly-ALR2, unlikely what observedfor glutathionyl-modified ALR2 (GS-ALR2), promotes the generation of an intramolecular disulfide bondbetween Cys298 and Cys303 residues. A rationale for the special susceptibility of Cys-ALR2 and CysGly-ALR2, as compared to GS-ALR2, to the thermally induced intramolecular rearrangement is given on thebasis of a molecular dynamic and energy minimization approach. A pathway of thiol/disulfideinterconversion for bovine lens ALR2 induced, in oxidative conditions, by physiological thiol compoundsis proposed.