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Article: Similarity of the yellow chromophores isolated from human cataracts with those from ascorbic acid-modified calf lens proteins: Evidence for ascorbic acid glycation during cataract formation

TitleSimilarity of the yellow chromophores isolated from human cataracts with those from ascorbic acid-modified calf lens proteins: Evidence for ascorbic acid glycation during cataract formation
Authors
KeywordsSpecies Index: Bovinae
Issue Date2001
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/bbadis
Citation
Biochimica et Biophysica Acta - Molecular Basis of Disease, 2001, v. 1537 n. 1, p. 14-26 How to Cite?
AbstractChromatographic evidence supporting the similarity of the yellow chromophores isolated from aged human and brunescent cataract lenses and calf lens proteins ascorbylated in vitro is presented. The water-insoluble fraction from early stage brunescent cataract lenses was solubilized by sonication (WISS) and digested with a battery of proteolytic enzymes under argon to prevent oxidation. Also, calf lens proteins were incubated with ascorbic acid for 4 weeks in air and submitted to the same digestion. The percent hydrolysis of the proteins to amino acids was approximately 90% in every case. The content of yellow chromophores was 90, 130 and 250 A330 units/g protein for normal human WISS, cataract WISS and ascorbate-modified bovine lens proteins respectively. Aliquots equivalent to 2.0 g of digested protein were subjected to size-exclusion chromatography on a Bio-Gel P-2 column. Six peaks were obtained for both preparations and pooled. Side by side thin-layer chromatography (TLC) of each peak showed very similar Rf values for the long wavelength-absorbing fluorophores. Glycation with [U-14C]ascorbic acid, followed by digestion and Bio-Gel P-2 chromatography, showed that the incorporated radioactivity co-eluted with the A330-absorbing peaks, and that most of the fluorescent bands were labeled after TLC. Peaks 2 and 3 from the P-2 were further fractionated by preparative Prodigy C-18 reversed-phase high-performance liquid chromatography. Two major A330-absorbing peaks were seen in peak 2 isolated from human cataract lenses and 5 peaks in fraction 3, all of which eluted at the same retention times as those from ascorbic acid glycated calf lens proteins. HPLC fractionation of P-2 peaks 4, 5 and 6 showed many A330-absorbing peaks from the cataract WISS, only some of which were identical to the asorbylated proteins. The major fluorophores, however, were present in both preparations. These data provide new evidence to support the hypothesis that the yellow chromophores in brunescent lenses represent advanced glycation endproducts (AGEs) probably due to ascorbic acid glycation in vivo. © 2001 Elsevier Science B.V. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/91015
ISSN
2015 Impact Factor: 5.158
2015 SCImago Journal Rankings: 2.718
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorCheng, Ren_HK
dc.contributor.authorLin, Ben_HK
dc.contributor.authorLee, K-Wen_HK
dc.contributor.authorOrtwerth, BJen_HK
dc.date.accessioned2010-09-17T10:11:46Z-
dc.date.available2010-09-17T10:11:46Z-
dc.date.issued2001en_HK
dc.identifier.citationBiochimica et Biophysica Acta - Molecular Basis of Disease, 2001, v. 1537 n. 1, p. 14-26en_HK
dc.identifier.issn0925-4439en_HK
dc.identifier.urihttp://hdl.handle.net/10722/91015-
dc.description.abstractChromatographic evidence supporting the similarity of the yellow chromophores isolated from aged human and brunescent cataract lenses and calf lens proteins ascorbylated in vitro is presented. The water-insoluble fraction from early stage brunescent cataract lenses was solubilized by sonication (WISS) and digested with a battery of proteolytic enzymes under argon to prevent oxidation. Also, calf lens proteins were incubated with ascorbic acid for 4 weeks in air and submitted to the same digestion. The percent hydrolysis of the proteins to amino acids was approximately 90% in every case. The content of yellow chromophores was 90, 130 and 250 A330 units/g protein for normal human WISS, cataract WISS and ascorbate-modified bovine lens proteins respectively. Aliquots equivalent to 2.0 g of digested protein were subjected to size-exclusion chromatography on a Bio-Gel P-2 column. Six peaks were obtained for both preparations and pooled. Side by side thin-layer chromatography (TLC) of each peak showed very similar Rf values for the long wavelength-absorbing fluorophores. Glycation with [U-14C]ascorbic acid, followed by digestion and Bio-Gel P-2 chromatography, showed that the incorporated radioactivity co-eluted with the A330-absorbing peaks, and that most of the fluorescent bands were labeled after TLC. Peaks 2 and 3 from the P-2 were further fractionated by preparative Prodigy C-18 reversed-phase high-performance liquid chromatography. Two major A330-absorbing peaks were seen in peak 2 isolated from human cataract lenses and 5 peaks in fraction 3, all of which eluted at the same retention times as those from ascorbic acid glycated calf lens proteins. HPLC fractionation of P-2 peaks 4, 5 and 6 showed many A330-absorbing peaks from the cataract WISS, only some of which were identical to the asorbylated proteins. The major fluorophores, however, were present in both preparations. These data provide new evidence to support the hypothesis that the yellow chromophores in brunescent lenses represent advanced glycation endproducts (AGEs) probably due to ascorbic acid glycation in vivo. © 2001 Elsevier Science B.V. All rights reserved.en_HK
dc.languageengen_HK
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/bbadisen_HK
dc.relation.ispartofBiochimica et Biophysica Acta - Molecular Basis of Diseaseen_HK
dc.subjectSpecies Index: Bovinaeen_HK
dc.titleSimilarity of the yellow chromophores isolated from human cataracts with those from ascorbic acid-modified calf lens proteins: Evidence for ascorbic acid glycation during cataract formationen_HK
dc.typeArticleen_HK
dc.identifier.emailLin, B:blin@hku.hken_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/S0925-4439(01)00051-5en_HK
dc.identifier.pmid11476959-
dc.identifier.scopuseid_2-s2.0-0035958673en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0035958673&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume1537en_HK
dc.identifier.issue1en_HK
dc.identifier.spage14en_HK
dc.identifier.epage26en_HK
dc.identifier.isiWOS:000170470300002-

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