Sucrose biosynthesis

Sucrose is synthesized from the precursors UDP-glucose and fructose 6-phosphate, which are converted into sucrose 6-phosphate by the enzyme sucrose-6-phosphate synthase. Sucrose 6-phosphate is then dephosphorylated by sucrose phosphatase, resulting in the formation of sucrose, which can be exported to other tissues. Although the reaction catalyzed by sucrose 6-phosphate synthase is energetically unfavorable, the hydrolysis of sucrose 6-phosphate to sucrose is highly exergonic, driving the overall synthesis of sucrose in an essentially irreversible manner.

蔗糖由前体UDP-葡萄糖和果糖-6-磷酸合成，这两者经蔗糖-6-磷酸合成酶催化转化为蔗糖-6-磷酸。随后，蔗糖-6-磷酸在蔗糖磷酸酶的作用下脱磷酸，生成蔗糖，蔗糖可被输送到其他组织。尽管蔗糖-6-磷酸合成酶催化的反应在能量上是不利的，但蔗糖-6-磷酸水解为蔗糖的过程具有高度放能特性，从而驱动蔗糖的整体合成过程以近乎不可逆的方式得以进行。