PDIA3 Human, Active

PDIA3 is primarily localized in the endoplasmic reticulum (ER), where it interacts with lectin chaperones such as calreticulin and calnexin . These interactions are essential for modulating the folding of glycoproteins by promoting the formation of disulfide bonds . The enzyme’s activity is vital for maintaining cellular homeostasis and ensuring the correct conformation of proteins, which is critical for their functionality .

The recombinant form of PDIA3 is produced using recombinant DNA technology. This involves cloning the PDIA3 gene into an expression vector, which is then introduced into a suitable host cell, such as Escherichia coli or yeast. The host cells are cultured under conditions that promote the expression of the PDIA3 protein. Once expressed, the protein is purified using various chromatographic techniques to obtain the active recombinant enzyme .

PDIA3 catalyzes several important chemical reactions involving disulfide bonds. These reactions include:

1. Formation of Disulfide Bonds: PDIA3 facilitates the formation of disulfide bonds between cysteine residues in nascent polypeptides, which is essential for the structural integrity of proteins.
2. Isomerization of Disulfide Bonds: The enzyme can rearrange incorrect disulfide bonds to ensure the proper folding of proteins.
3. Reduction or Oxidation of Disulfide Bonds: PDIA3 can also reduce or oxidize disulfide bonds, depending on the cellular redox state .

The activity of PDIA3 is typically analyzed using biochemical assays that measure its ability to catalyze these reactions. These assays often involve substrates that mimic the natural substrates of PDIA3 and can be monitored using spectroscopic or chromatographic methods .

PDIA3 is involved in various biological processes, including the unfolded protein response (UPR), which is activated in response to the accumulation of misfolded proteins in the ER. By ensuring the proper folding of glycoproteins, PDIA3 helps maintain protein homeostasis and prevent cellular stress .