Abstract Despite physiological importance of aldonic sugar acids for living organisms, little is known about metabolic pathways of these compounds. Here, we investigated the functional diversity of homologs of L-threonic acid dehydrogenase (ThrDH; UniProt ID: Q0KBC7), an enzyme composed of two NAD-binding domains (PF14833 and PF03446). Ten ThrDH homologs with different genomic context were studied; seven new enzymatic activities were identified, such as ( R )-pantoate dehydrogenase, L-altronic acid dehydrogenase, 6-deoxy-L-talonate dehydrogenase, L-idonic acid dehydrogenase, D-xylonic acid dehydrogenase, D-gluconic acid dehydrogenase, and 2-hydroxy-3-oxopantoate reductase activities. Two associated metabolic pathways were identified: L-idonic acid dehydrogenase was found to be involved in the degradation of L-idonic acid through oxidation/decarboxylation in Agrobacterium radiobacter K84, while 2-hydroxy-3-oxopantoate reductase was found to participate in D-glucarate catabolism through dehydration/cleavage in Ralstonia metallidurans CH34.

中文翻译：

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L-苏糖酸脱氢酶同源物的底物多样性

摘要 尽管醛糖酸对生物体具有生理学重要性，但对这些化合物的代谢途径知之甚少。在这里，我们研究了 L-苏糖酸脱氢酶（ThrDH；UniProt ID：Q0KBC7）同系物的功能多样性，该酶由两个 NAD 结合域（PF14833 和 PF03446）组成。研究了具有不同基因组背景的 10 个 ThrDH 同源物；鉴定了 7 种新的酶活性，例如 (R)-泛解酸脱氢酶、L-丙二醛酸脱氢酶、6-脱氧-L-塔龙酸脱氢酶、L-艾杜糖酸脱氢酶、D-木糖酸脱氢酶、D-葡萄糖酸脱氢酶和2-羟基-3-氧代泛酸还原酶活性。确定了两个相关的代谢途径：