Abstract:In order to further elucidate the physiological function of metallothionein from tartary buckwheat Fagopyrum tataricum (FtMT), recombinant FtMT and CPP-FtMT including 11R-FtMT and Tat-FtMT were produced, which were fused with cell-penetrating peptides (CPPs), by a novel secreted expression method using phoA vector in Escherichia coli (E. coli). Three types of proteins were purified by Ni2+ affinity chromatography followed by induction of a low concentration of phosphate and were by identified by SDS-PAGE, Western blot and UV absorption spectrometry. Chemical and functional characteristics of three types of proteins were analyzed including by metal-binding capacity and hydroxyl radical scavenging ability. The results showed three types of proteins have almost the same motif of UV absorption spectrometry and exhibited intact metal binding ability and hydroxyl radical scavenging ability. Cell penetrating ability of CPP-FtMT proteins was investigated using FITC labeled peptide internalization into Ins-1 beta cells and H9c2 cardiomyocytes under fluorescent microscopy. Moreover, Ins-1 beta cells and H9c2 cardiomyocytes were treated with CPP-FtMT to reveal protective effects against glucolipotoxicity-induced and hyperglycemia-induced apoptosis with or without hypoxia, respectively. The results demonstrated CPP-FtMT proteins strongly protected Ins-1 beta cells against oxidative stress and apoptosis induced by glucolipotoxicity with or without hypoxia, and also protected H9c2 cardiomyocytes against hyperglycemia-induced apoptosis with or without hypoxia. These present studies provide a scientific basis for the development and application of FtMT.