Identification of the site of glycation of γ-II-crystallin by (14C)-fructose

Pennington, J. H.; Harding, John J.

doi:10.1016/0925-4439(94)90024-8

Cited by 17 publications

(9 citation statements)

References 28 publications

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“…Our data showed that L-and Q-crystallins were susceptible to glycation by fructose, and Zhao et al [16] showed the sites of glycation in L-crystallin by fructose. Although Pennington et al [17] and Smith et al [18] reported the sites of glycation in Q-crystallin by fructose, we further investigated the Q-crystallin situation.…”

Section: Discussionmentioning

confidence: 99%

Specific detections of the early process of the glycation reaction by fructose and glucose in diabetic rat lens

et al. 1998

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The glycation reaction by fructose, as well as that by glucose, in control and diabetic rat lens was analyzed by using antibodies which specifically recognize adducts of lysine with fructose and with glucose. Levels of fructose adducts in diabetic rat lens were 2.5 times that of the control, and correlated with sorbitol levels. This was mainly due to enhanced glycation of L Land Q Q-crystallins by fructose under diabetic conditions. These data suggest that glycation by fructose may also play a role in cataract formation under conditions of diabetes and aging.z 1998 Federation of European Biochemical Societies.

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Section: Discussionmentioning

confidence: 99%

Specific detections of the early process of the glycation reaction by fructose and glucose in diabetic rat lens

et al. 1998

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“…A column was packed with aminoethyl succinyl aminophenylboronate covalently attached to the matrix. The gel has an affinity for sugar groups and should pull out fructose-labelled proteins from the pool of unlabelled proteins [27]. A buffer containing 0.25 M ammonium acetate, pH 8.5, was used for column equilibration and for eluting non-glycated proteins at a rate of 18 ml\h.…”

Section: Affinity Chromatography Of Glycated Enzymesmentioning

confidence: 99%

Glycation-induced inactivation and loss of antigenicity of catalase and superoxide dismutase

Zhang

Harding

1997

Biochemical Journal

228

113

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Oxidative mechanisms are thought to have a major role in several biological phenomena, including cataract formation and diabetic complications. Here we investigate the inactivation of catalase and superoxide dismutase, both powerful antioxidant enzymes, by sugars of different glycating abilities, and the loss of antigenicity that was monitored by the loss of activity after immunoprecipitation with monospecific antibodies. The antigenicity of non-glycated or glycated enzymes separated by affinity chromatography were determined by dot-blotting. Incubation with sugars resulted in a time-dependent inactivation of the enzymes. Ribose and fructose inactivated them more rapidly than glucose and glucose 6-phosphate. Glycation induced losses of antigenicity and inactivation simultaneously. The glycated enzymes had entirely lost their antigenicity compared with non-glycated enzyme. These results further support the idea that inactivation of enzyme and loss of antigenicity are simultaneous. This might occur in the pathogenesis of diabetic complications and aging.

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“…From our results, it is clear that lysine, although only weakly glycated, is important for glycation-mediated cross-linking, and the ␣-amino group of ␥B-crystallin, despite being a major glycation site (19,20,30), has much less ability to cross-link with itself or with other residues. Therefore, cross-linking ability depends not only upon the level of glycation but also upon which amino group is glycated.…”

Section: Discussionmentioning

confidence: 82%

The Role of α- and ε-Amino Groups in the Glycation-mediated Cross-linking of γB-crystallin

Zhao¹,

Nagaraj²,

Abraham³

1997

Journal of Biological Chemistry

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In the previous report we demonstrated that ␥B-crystallin is glycated predominantly at the N-terminal ␣-amino group (Casey, E. B., Zhao, H. R., and Abraham, E. C. (1995) J. Biol. Chem. 270, 20781-20786). To investigate the possible role of ␣-and ⑀-amino groups of ␥B-crystallin in glycation-mediated cross-linking, Lys-2 or Lys-163, or both, were mutated to threonine by site-directed mutagenesis in bovine ␥B-crystallin cDNA. Wild type and mutant ␥B-crystallins were expressed in Escherichia coli cells. Cross-linking studies were performed by incubating wild type and mutant ␥B-crystallins with glyceraldehyde, ribose, and galactose followed by SDS-polyacrylamide gel electrophoresis under reducing conditions. When both of the lysines of ␥B-crystallin were mutated to threonines (␥B-K2T/K163T), the quantity of cross-linked products was greatly reduced, indicating that, despite the fact that the ␣-amino group is a major glycated site, ⑀-amino groups play a predominant role in cross-linking. Therefore, cross-linking ability depends not only upon the level of glycation but also upon which amino group is glycated. Steric hindrance may decrease the cross-linking ability of the ␣-amino group. Our results also show that Lys-2 and Lys-163 play almost equal roles in cross-linking of ␥B-crystallin. By incubating carbonic anhydrase, a protein with a blocked N terminus, and our novel "no lysine" ␥B (␥B-K2T/K163T) with sugar, we were able to show for the first time that significant cross-linking occurs between lysines and non-lysine sites. The fact that pentosidine and imidazolysine, formed from ribose and methylglyoxal, respectively, were present in the cross-linked ␥B-crystallins revealed the existence of Lys-Arg and Lys-Lys cross-linking.

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Identification of the site of glycation of γ-II-crystallin by (14C)-fructose

Cited by 17 publications

References 28 publications

Specific detections of the early process of the glycation reaction by fructose and glucose in diabetic rat lens

Specific detections of the early process of the glycation reaction by fructose and glucose in diabetic rat lens

Glycation-induced inactivation and loss of antigenicity of catalase and superoxide dismutase

The Role of α- and ε-Amino Groups in the Glycation-mediated Cross-linking of γB-crystallin

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