The preparation and characterization of novel human-like collagen metal chelates

In order to develop the nutritional trace elements which could be absorbed and utilized effectively, protein chelates were adopted. Calcium, copper and manganese were considered based on their physiological functions, and the new chelates of HLC-Ca, HLC-Cu and HLC-Mn were formed in MOPS or MES buffer and purified by gel chromatography, and then freeze-dried. And they were detected and analyzed by atomic absorption spectrophotometry, ultraviolet–visible absorption (UV–vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, fluorescence quenching method, circular dichroism (CD) and differential scanning calorimetry (DSC). The results showed that some chemical reactions happened between HLC and the three metal ions to form new chemical compounds. The thermodynamic parameters, ∆H, ∆G and ∆S, showed that the chelation process between HLC and metal ions was performed spontaneously. Fluorescence quenching spectra of HLC indicated that the quenching mechanism was static in nature. According to the data of DSC, the new chelates were more stable than the free HLC. And HLC-metal complex was non-toxic to the BHK21 cell through MTT assay.