Characterization of Genes Encoding Protein Disulfide Isomerase in Wheat Including the Specific Role of PDI in the Formation of Gluten

The results of phylogenetic analyses revealed that the family of plant PDI may comprise of at least eight different subfamilies with varying numbers and positions of active centers while retention signals in the endoplasmic reticulum may be present or absent. At least one gene has been cloned for each phylogenetic group. Other phylogenetic analyses have indicated that the family of PDI-like proteins consists of ten classes, the first five of which include proteins equipped with two thioredoxin domains. These results indicate complexity and diversity of the family of protein disulfide isomerase in plants. The study of molecular characteristics of PDI in some cereal species have shown that this enzyme participates in the maturation of secretory proteins and also in the formation of albuminous substances in endosperm, in the mechanism of formation of disulfide bonds and polymerization of gluten polypeptides in wheat. The mechanism of formation of disulfide linkage was tested through in vitro experiments. However, it is not entirely certain whether it reflects their formation in vivo. The results of researches suggest that protein folding and disulfide bond formation occurs in the endoplasmic reticulum. PDI plays a prominent role among enzymes involved in posttranslational modification of proteins. The main goal of this work is to present research data on protein disulfide isomerase, which may be a leading research objective in the area of wheat gluten and the impact of PDI on the baking quality of wheat flour.