Fc-l-pro-l-leu - Gly-ome, Ferrocene - Peptide Synthesis, Structural Analysis And Its Electrochemical Properties

Ferrocene and its derivatives due to their biological activity, high lipophhilicity, redox activity, stability, low cytotoxicity and distinctive electrochemical behavior have been widely used in biology, medicine and microbiology.PLG (L-Prolyl-L-Leucyl-Gly-OMe) is an endogenous tripeptide found in the central nervous system, it is also known as melanocyte-stimulating release inhibiting factor-1 (MIF-1). It can control the release of melanocyte-stimulating hormone (MSH). A number of clinical studies have showed that PLG possessed substantial therapeutic activities in Parkinson's disease.Firstly, the ferrocene conjugates Fc-Pro-Leu-Gly-OMe and Fc-Pro-Leu-Gly-NH2 were synthesized from ferrocene, proline, leucine, glysine acid by liquid phase synthesis, using HBTU and HOBt as coupling agents. The structure of the compound was characterized by IR-spectrum, UV-vis spectrum,1H NMR and ESI-MS. Their yields were 31% and 25%.Secondly, The Fc-PLG crystal structure was analytical at-100℃by diffraction. The crystal was monoclinic, space group C2 with the cell parameter is a=20.803(3) A, b=6.4428(4) A, c=20.557(2) A, a=90°,β=115.498(5)°, y=90°,Z=4, R=0.0451. The twist angle between Cp rings is 178.4°,the amide plane is rotated out of the Cp ring plane by 14.1°. A strong hydrogen bond between the Gly amide nitrogen N13 and Pro amide oxygen is typical for the structure motif of a P-turn. (d(N-O)=2.835A).A method of CV (Cyclic Voltammetry) was carried out to observe the electrochemical properties of Fc-Pro-Leu-Gly-OMe and it was proved that it was a quasireversible electrochemical process in methanol, the oxidation potential (Ea) and reduction potential (Ec) were observed at 0.475 V and 0.372 V, The oxidation peak shifted about 83 mV to anodic and the ratio of ipa and ipc was 1.012.