Molecular cloning and characterization of regulatory enzymes in threonine biosynthetic pathway from soybean

Soybeans (Glycine max [L.] Merr.) are a good source of protein and oil. In addition to its importance in the human diet, this crop plays a major role as an important component of animal feed, along with corn. Despite being a very good source of protein, soybeans nutritional value is limited by low proportion of sulfur amino acids methionine and cysteine. Hence, achieving a favorable amino acid composition of soybean protein has been an objective of researchers for a long time. Recently, synthetic amino acids are being added to soy/corn based animal feeds in order to supplement the limited amino acids. The cost involved aside, other essential amino acids, called secondtier amino acids, are also becoming limiting in animal feed due to addition of synthetic amino acids. Threonine is one of those second-tier amino acids and improving its proportion in soybean seeds can improve the nutritional value of soy-based animal feed. The manipulation of key regulatory enzymes in the biosynthesis pathway of this