**50. Soybean ATP sulfurylase**

Analysis of the ATP sulfurylase ATPS clone isolated from a soybean seedling cDNA library revealed an open-reading frame, encoding a 52-kDa polypeptide with an Nterminal chloroplast/plastid transit peptide. ATP sulfurylase mRNA was present with the highest abundance in root tissue. mRNA accumulated and the specific activity of ATP sulfurylase in root tissue was enhanced by cold treatment. The transcript levels and specific activity of the enzyme dropped during the later stages of seed develop‐ ment. Augmenting the expression levels of this key enzyme during soybean seed de‐ velopment could increase the availability of sulfur amino acids and elevate the nutritional value of the crop [54].
