NBD-Cl与头发表面半胱氨酸残基的相互作用研究

In this work, thioglycolic acid was used as a reducing agent in the disconnection of –SS- groups under alkaline condition which make cystine transfer to cysteine residue on hair curticle. The reaction between NBD-Cl and cysteine residue of human hair was investigated with attenuated total reflection fourier transform infrared spectroscopy (ATR FT-IR) and fluorescence spectrometry. The results indicate that the λem-max from treated hair surface displayed red shift with increasing pH between 2~5 and the reaction of the cysteine with NBD-Cl is pH-dependent. The thiol group of cysteine of treated hair could be substituted by NBD-Cl. This supposal was further conformed with NO2 symmetric stretching vibration was found in the ATR FT-IR spectra of hair samples treated with NBD-Cl at pH3 medium. The selectivity of reaction on submitted group (thiol or amine) was not influenced with NBD-Cl concentration. The existence of some cationic ions, such as Cu2+, Pb2+, Fe3+would weaken the reaction, while Ni2+ has no obvious effect.