Preparation of UDP-galacturonic acid using UDP-sugar pyrophosphorylase
Preparation of UDP-galacturonic acid using UDP-sugar pyrophosphorylase
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DOI：
10.1016/j.ab.2006.02.026
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发表时间：
2006-05-15
影响因子：
2.9
通讯作者：
Hase, Sumihiro
中科院分区：
文献类型：
--
作者：
Ohashi, Takao;Cramer, Nicolai;Hase, Sumihiro
udp -半乳糖醛酸是半乳糖醛酸（GalUA）的活化形式，可通过新生和回收途径合成。参与救助途径的UDP-GalUA焦磷酸化酶基因尚未确定。本研究表明，来自Pisum sativum的具有广泛特异性的udp -糖焦磷酸化酶具有UDP-GalUA焦磷酸化酶活性。该酶催化GalUA i -磷酸和UTP生成UDP-GalUA和焦磷酸，平衡常数值为0.24。重组udp -糖焦磷酸化酶的最适pH为6.0，GalUA i -磷酸、UTP、UDP-GalUA和焦磷酸的表观K-m值分别为2.27、1.15、0.70和1.26 mM。在无机焦磷酸酶的存在下，重组酶在制备规模上以84%的产率（基于GalUA 1-磷酸底物）产生UDP-GalUA。因此，该酶可用于果胶生物合成研究中高效生产UDP-GalUA。(c) 2006爱思唯尔公司版权所有。
UDP-galacturonic acid, the activated form of galacturonic acid (GalUA), is synthesized both de novo and by salvage pathways. The UDP-GalUA pyrophosphorylase gene involved in the salvage pathway has not been identified. Here we show that UDP-sugar pyrophosphorylase from Pisum sativum with a broad specificity has UDP-GalUA pyrophosphorylase activity. The enzyme catalyzed the formation of UDP-GalUA and pyrophosphate from GalUA I-phosphate and UTP with an equilibrium constant value of 0.24. The recombinant UDP-sugar pyrophosphorylase had optimal pH of 6.0, and the apparent K-m values for GalUA I-phosphate, UTP, UDP-GalUA, and pyrophosphate were 2.27, 1.15, 0.70, and 1.26 mM, respectively. In the presence of inorganic pyrophosphatase, the recombinant enzyme produced UDP-GalUA in an 84% yield (based on the GalUA 1-phosphate substrate) on a preparative scale. Thus, this UDP-sugar pyrophosphorylase is useful for the highly efficient production of UDP-GalUA for studies on pectin biosynthesis. (c) 2006 Elsevier Inc. All rights reserved.