Vaspin Human, His

Vaspin, also known as visceral adipose-specific serpin or SERPINA12, is a member of the serine protease inhibitor family. It is a newly identified adipokine, predominantly expressed in visceral white adipose tissues. Vaspin has garnered significant interest due to its unique role as an insulin-sensitizing adipocytokine, particularly in the context of obesity .

Human recombinant vaspin is produced in Escherichia coli and is a single, non-glycosylated polypeptide chain containing 415 amino acids. It has a molecular mass of approximately 47 kDa . The recombinant protein is tagged with a His (histidine) tag, which facilitates its purification through affinity chromatography techniques .

The amino acid sequence of human recombinant vaspin includes several distinctive structural features typical of the serpin family, such as three beta-sheets, nine alpha-helices, and one central loop . These structural elements are crucial for its function as a serine protease inhibitor.

Vaspin’s primary function is as a serine protease inhibitor, although its specific protease targets are still under investigation. It exhibits approximately 40.2% sequence identity with alpha1-antitrypsin, another well-known serpin . Vaspin’s expression in visceral fat is positively correlated with body mass index (BMI) and body fat percentage .

Vaspin plays a significant role in glucose metabolism and insulin sensitivity. Studies have shown that the administration of vaspin to obese mice improves glucose tolerance and insulin sensitivity, leading to normalized blood glucose levels . This makes vaspin a potential therapeutic target for metabolic disorders such as obesity and type 2 diabetes.

The production of human recombinant vaspin involves the expression of the protein in Escherichia coli. The His tag attached to the protein allows for its purification using affinity chromatography, resulting in a highly purified product with a purity greater than 90% as determined by SDS-PAGE . The protein is typically formulated in a buffer containing 20mM Tris (pH 8), 0.2mM PMSF, and 10% glycerol .

Human recombinant vaspin is stable at 10°C for up to one week but should be stored below -18°C for long-term storage. To prevent degradation, it is recommended to add a carrier protein such as 0.1% human serum albumin (HSA) or bovine serum albumin (BSA) and to avoid freeze-thaw cycles .

Vaspin is primarily used in laboratory research to study its role in metabolism, obesity, and related metabolic disorders. It is also utilized in various assays, including Western blotting, ELISA, and functional assays, to investigate its biological functions and interactions .