摘要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 γ-crystallins with cyanate.The carbamylated amino acids obtained by this procedure are alanine and hlycine,which are N-terminal amino acids of γ-crystallin,and leucine.The aggregate,which can be observed in carbamylated γ1-crystallin on SDS-PAGE,may be related to the formation of disulfide and non-disulfide covalent bonds,and it seems that γ2 and γ3-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;γ-crystallin may play a very important role in the formation of cataract associated with accumulation of cyanate in human body,such as heavy smoking.