Investigation Of Electron Transfer Of Cytochromes On Transition Metals By SERS Spectroscopy

Cytochrome is an important heme protein,which participates in a variety of biological processes.Studies on structure and function of cytochrome in vitro are ofo great importance in many fields including clinical medicine and cancer biochemistry.Surface-enhanced Raman scattering?SERS?spectroscopy has properties of high sensitivity,good selectivity and no interference from water for the detection of biological samples.In this thesis,we investigated electron transfer?ET?of cytochromes on transition metals by SERS spectroscopy,and discussed the mechanisms of the ET between them.This study provides biocompatible substrates for SERS-based studies on proteins,and has extended the application areas of transition metals to spectroscopic investigation of redox proteins.The major research contents are as follows:?1?.Study on the ET of cytochromes on nickel island films.The structure of cytochrome b₅?Cyt b₅?,cytochrome c?Cyt c?and myoglobin?Mb?on nickel island films were obtained by surface enhanced resonance Raman scattering?SERRS?spectroscopy.The results indicated that Cyt b₅ had a similar high affinity to nickel surface as Cyt c,while the affinity between Mb and nickel was rather weak.Direct ET between Ni and Cyt b₅/Cyt c was found to be p H-dependent.Additionally we found the adsorbed Cyt b₅ with intact bioactivity could transfer electrons to Met Mb,which confirmed the biocompatibility of the nickel supports.Moreover,the Raman enhancement ability of the nickle was improved by rougheningthe substrates by electrochemistry.?2?.Study on biocompatibility and ET mechanism of cytochrome c on transition metal nanomaterials.SERS active noble metal and transition metal nanomaterials were synthesized and the ET between Cyt c and these nanomaterials was explored by SERS spectroscopy.The results showed that the ET between the reduced Cyt c and the silver nanoparticles has a laser wavelength dependence,but the nickel and cobalt nanomaterials reacted directly with the oxidized state Cyt c,independent on the laser.Moreover,the nickel and cobalt nanomaterials were found to display Cyt c reductive activity.Compared to the noble metals,transition metals have better biocompatibility.We also discussed the ET mechanism between Cyt c and noble metals or transition metals.