Function, structure and catalytic mechanism of sucrose phosphate synthase: a review / 生物工程学报

Sucrose is a natural product occurs widely in nature. In living organisms such as plants, sucrose phosphate synthase (SPS) is the key rate-limiting enzyme for sucrose synthesis. SPS catalyzes the synthesis of sucrose-6-phosphate, which is further hydrolyzed by sucrose phosphatase to form sucrose. Researches on SPS in recent decades have been focused on the determination of enzymatic activity of SPS, the identification of the inhibitors and activators of SPS, the covalent modification of SPS, the carbohydrate distribution in plants regulated by SPS, the mechanism for promoting plant growth by SPS, the sweetness of fruit controlled by SPS, and many others. A systematic review of these aspects as well as the crystal structure and catalytic mechanism of SPS are presented.

Effect of putrescine on sucrose metabolism and triterpenoid accumulation in Betula platyphylla suspension cells / 中草药

Objective: To analyze the effect of exogenous putrescine on triterpenoid accumulation and sucrose metabolism. Methods: Putrescines (0.1, 1, and 5 mmol/L) were added to the eight-day-old suspension cell culture, and the content changes of sucrose, fructose, glucose, and triterpenoid, the activity of sucrose phosphate synthase (SPS) and sucrose synthase (SS) were analyzed by colorimetry. Results: Putrescine increased the content of sucrose in cells but decreased the conent in culture medium. Among them, the content of sucrose was most enhanced after putrescine induction for 6 h; The increasing rate was 169.41%. However, the contents of fructose and glucose were only increased in 6 h under the putrescine treatment, the other treatments decreased the contents of fructose and glucose. In addition to 5 mmol/L putrescine treatment, putrescine enhanced the activities of SPS and SS. The content of triterpenoid in suspension cells was increased in 12 h after 5-40 g/L sucrose induction, and the content of triterpenoid was most induced by 20 g/L sucrose, the increasing rate was 52.16%. In addition to increasing 27.37% on triterpenoid content in cells treated by 1 mmol/L putrescine and 5 g/L sucrose, the treatment of 1 mmol/L putrescine and other sucrose concentration decreases the accumulation of triterpenoid. Conclusion: Putrescine could increase the sucrose content and triterpenoid accumulation in suspension cell culture, and we preliminarily inferred that the induction of sucrose by putrescine could participate in the accumulation of triterpenoid in birch cells.