Carbamylation of human lens gamma-crystallins: relevance to cataract formation.
Cigarette smoking is a main source of cyanide in human body, which can be taken as a risk factor of cataract formation. In this study, combined gas chromatography and mass spectrum (GC/MS) was used to determine the amino acid hydantoin after the incubation of soluble human lens gamma-crystallins with cyanate. The carbamylated amino acids obtained by this procedure are alanine and glycine, which are N-terminal amino acids of gamma-crystallin, and leucine. The aggregate, which can be observed in carbamylated gamma 1-crystallin on SDS-PAGE, may be related to the formation of disulfide and non-disulfide covalent bonds, and it seems that gamma 2 and gamma 3-crystallins can not be aggregated to any great extend. The results in this study indicate that the GC/MS is an effective method for analyzing the carbamylation of lens proteins; gamma-crystallin may play a very important role in the formation of cataract associated with accumulation of cyanate in human body, such as heavy smoking.
Liu
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Zhongshan Ophthalmic Center, Sun Yat-Sen University of Medical Sciences, Guangzhou, China.
Li
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D002386:Cataract / Q000209:etiology; D003459:Crystallins / Q000187:drug effects*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007908:Lens, Crystalline / Q000187:drug effects*; D008297:Male; D011190:Potassium Cyanide / Q000494:pharmacology*; D012907:Smoking / Q000009:adverse effects
D003459:Crystallins; D011190:Potassium Cyanide