Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An unusual pink compound has been isolated from the proteolytic digests of senile nuclear cataract proteins by adsorption onto Sephadex G-10. The tiny amounts obtained precluded definitive structural elucidation, however TLC comparisons show that it resembles triphenodioxazine-1,8-dicarboxylic acid, a pink heterocyclic chemical formed by oxidative condensation of 3-hydroxyanthranilic acid.
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PMID:An unusual coloured compound in digests of senile nuclear cataract lens proteins. 137 44

This study deals with the effects of the SH oxidizing agent diamide (diazene dicarboxylic acid bis-(N,N-dimethyl-amide)) on the water-soluble proteins from rabbit lenses. The dialyzed protein extracts were incubated for 0.5-1.5 h with various concentrations of diamide. Alterations in sulphydryl contents, gel filtration and gel electrophoresis profiles of proteins were recorded. The response to 2 mM diamide treatment for 1 h consists of rapid oxidation (up to 40%) of protein-bound sulphydryl groups accompanied by appearance of polypeptides with apparent molecular weights in excess of 68,000. A protein with a molecular weight of 29 kDa was shown to be specially involved in cross-linking. The linkages in the dialyzed water-soluble lens protein fraction induced by diamide may be reduced by GSH (10 mM) treatment of the protein extract. The main target of oxidative insult induced by diamide in the water-soluble proteins of the lens is probably the superficially localized sulphydryl groups of crystallins. Our observations suggest that this oxidative system of proteins may be a useful tool for cataract research.
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PMID:Diamide-induced cross-linking of the lens water-soluble proteins as a model of the early oxidative changes during senile cataract formation. 208 97

The study has examined the effects of the SH-oxidizing agent diamide (Diazane dicarboxylic acid bis-(N,N-dimethyl-amide)) on the water-soluble portion of proteins from rabbit lenses. The dialyzed protein extracts were incubated for 1-1.5 hrs with various concentrations of diamide. Treatments were monitored for alterations in sulphydryl contents, gel filtration and gel electrophoresis profiles of proteins. The response to 2 mM diamide treatment for 1 hr consists of rapid oxidation (up to 40%) of protein-bound sulphydryl groups accompanied by an appearance of polypeptides with apparent molecular weights. The protein with molecular weight of 29 kilodaltons was shown to be involved in cross-linking. The linkages in the dialyzed water-soluble lens polypeptide fraction induced by diamide may be reduced by GSH (10 mM) treatment of protein extract. The main target of oxidative insult induced by diamide in the water-soluble proteins of the lens is probably the superficially localized sulphydryl groups of crystallins. Our observations suggest that the described oxidative system of proteins may be a useful tool for cataract research.
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PMID:[Oligomerization of water soluble proteins of rabbit crystalline lens under the action of diamide]. 226 11

Based on previous findings that lens pigments and melanins share many physicochemical properties, human lens pigments and natural (hair) and synthetic melanins were submitted to oxidation with permanganate under strong acidic conditions. This procedure has been utilized for the characterization of melanins and results in the well defined products, thiazole-4,5-dicarboxylic acid (TDCA) and pyrrole-2,3,5-tricarboxylic acid (PTCA), which can be quantitated by high performance liquid chromatography (HPLC). PTCA is regarded as a marker of black eumelanins and was therefore a main component of synthetic DOPA-eumelanin and dark hair. Its identity was established by synthesis from 5-hydroxyindole-2-carboxylic acid. TDCA derives from pheomelanins and was therefore an important component of red hair and synthetic GSH-pheomelanin. TDCA was identified by its retention time relative to PTCA. The analysis of a series of cataract digests of increasing pigmentation (type I < type IV < type V) and a purified fraction of lens pigments (DE52 pigment) revealed the presence in these preparations of both PTCA and TDCA. The concentration of TDCA significantly increased with the degree of pigmentation of the digests and reached a maximum in the DE52 pigment. The TDCA/PTCA ratio was high in the lens preparations and comparable to that given by hair pheomelanin. These findings support that pheomelanin is an integral part of lens pigments. By comparing the yields of TDCA in GSH-pheomelanin and in the purified lens pigment, a 9% contribution of pheomelanin to the lens pigment was estimated.
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PMID:Melanins and lens pigments: a comparative study. 821 Feb 84