Synthesis, characterization, antioxidant and anti‐diabetic activities of a novel protein–vanadium complex

Abstract

The protein–vanadium complex was successfully synthesized and systematically characterized using electron paramagnetic resonance, Fourier transform‐infrared spectroscopy and thermogravimetric analysis. The antioxidant activity analysis indicated that it had better radical scavenging activity on 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), 2,2′‐azinobis (3‐ethylbenzothiazoline)‐6‐sulfonic acid (ABTS) and O2− compared with the free protein and vanadate. Additionally, the complex exhibited high anti‐diabetic activity against Saccharomyces cerevisiae α‐glucosidase and rat intestinal maltase with IC50 values of 258.53 and 72.41 μg/ml, respectively. Kinetics study showed that the complex was a mixed inhibition type against S. cerevisiae α‐glucosidase and uncompetitive inhibition type against rat intestinal maltase. These indicated that the complex with antioxidant and anti‐diabetic potential could be used for lowering blood glucose that might be caused by insufficient secretion of insulin in the body or excess fat storage. Our findings provide a new protein–vanadium complex for further use in diabetes mellitus or obesity.

Vanadium-protein complex inhibits human adipocyte differentiation through the activation of β-catenin and LKB1/AMPK signaling pathway

“…Our previous work showed that the synthetic V-P complex had high antidiabetic activity in vitro [24]. Here, the effect of different concentration of V-P complexes on the human preadipocyte differentiation was determined.…”

“…Additionally, our previous study showed that the synthetic vanadium-protein complex had antidiabetic activity in vitro [24]. It has been demonstrated that vanadium complexes with proper organic ligands can enhance vanadium's liposoluble properties, promote gastrointestinal absorption, tissue uptake and reduce the toxicity of the vanadium [25].…”

“…The V-P complex was synthesized according to the method of Zhang and Kim [24]. Briefly, 500 μg of recombinant human sentrin-specific protease 8 (N-6His) (26.2 kDa) was loaded to a Sephacryl S-200 HR column (1.0 × 10.0 cm) equilibrated with a binding buffer (1 mM VS, 1 mM iminodiacetic acid, 100 mM NaCl, 10 mM Tris, pH 7.4), and then eluted with binding buffer at a flow rate of 0.3 mL/min.…”

“…Therefore, we prepared the V-P complex by the reaction of vanadyl sulfate and recombinant human sentrin-specific protease 8 (N-6His) on Sephacryl S-200 HR column. The V-P complex was fond to exhibit antioxidant and anti-diabetic activity [24]. The molecular weight of 26.2 kDa of recombinant human sentrin-specific protease 8 (N-6His) contained about 212 amino acid residues, the ratio of amino acid residue to vanadium ions V would be 1: (>2).…”

“…The molecular weight of 26.2 kDa of recombinant human sentrin-specific protease 8 (N-6His) contained about 212 amino acid residues, the ratio of amino acid residue to vanadium ions V would be 1: (>2). The vanadium concentration of the V-P complex was determined to 0.1 mg/kg [24]. Although the dialysis was carried out, the V-P complexes might be not a pure compound but a mixture of vanadium-protein complexes and none specific bound vanadyl iminodiacetate.…”