Purification and structure analysis of zinc‐binding protein from Mizuhopecten yessoensis

Zn‐binding protein was obtained after purification from scallops (Mizuhopecten yessoensis) using gel permeation and ion‐exchange chromatography. Amino acid determination showed that the cysteine of the zinc‐binding protein accounted for one‐third of the total amino acids, which is a typical feature of metallothionein (MT). The spectra of Fourier Transform Infrared Spectroscopy (FTIR) and Circular Dichroism (CD) were analyzed to predict the secondary structure information of zinc‐binding protein: the α‐helix was 46.55%, the β‐sheets was 27.07%, the random coil was 16.48%, and the β‐turns was 9.89%. Using a commercial kit to measure its antioxidant activity in vitro, the result showed that it had good scavenging ability to 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), hydroxyl radical (·OH), and reducing the ability to ferrous iron ions. With the process provided by this study, zinc‐binding protein can be prepared in large quantities, which is the basis for its future commercialization. Practical applications According to the extraction and purification process established in this study, a large amount of zinc‐bound MT from the viscera of scallops can be obtained. And the zinc‐bound MT had good antioxidant activity. In addition, the yield of each purification step has been calculated. The zinc‐bound MTs from scallop’ viscera can be prepared in large quantities by directly using the process in this manuscript or by equal magnification of this process. In the future, large‐scale production can be considered to increase the economic value of scallops’ viscera. Zinc‐binding protein (F1‐2) was obtained after purification using gel permeation and ion‐exchange chromatography. The amino acid composition of F1‐2 showed the cysteine accounted for one‐third of the total amino acids, consistent with the molecular properties of a family of metallothionein proteins and at the same time, F1‐2 had better antioxidant capacity. With the process provided by this study, zinc‐binding protein can be prepared in large quantities, which is the basis for its future commercialization.