Shojima S, Nishizawa N K, Fushiya S, Nozoe S, Irifune T, Mori S
Laboratory of Plant Nutrition & Fertilizers, Department of Agricultural Chemistry, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113, Japan.
Plant Physiol. 1990 Aug;93(4):1497-503. doi: 10.1104/pp.93.4.1497.
2' -Deoxymugineic acid (DMA), one of mugineic acid-family phytosiderophores (MAs), was synthesized in vitro both from l-methionine and from nicotianamine (NA) with a cell-free system derived from root tips of iron-deficient barley (Hordeum vulgare L.). The reactions producing DMA from NA needed an amino group acceptor (i.e. 2-oxoglutarate, pyruvate, or oxalacetic acid) and a reductant (i.e. NADH or NADPH). The activity of the enzymes to produce NA from l-methionine was the highest at about pH 9. This biosynthetic activity was markedly induced by iron-deficiency stress. The synthesis of NA from S-adenosyl-l-methionine was more efficient than from l-methionine. From the results with the cell-free system reported here, we propose a revised biosynthetic pathway of MAs.
2'-脱氧 mugineic 酸（DMA）是 mugineic 酸家族植物铁载体（MAs）之一，在体外由 l-蛋氨酸和烟酰胺（NA）利用缺铁大麦（Hordeum vulgare L.）根尖来源的无细胞系统合成。由 NA 生成 DMA 的反应需要一个氨基受体（即 2-氧代戊二酸、丙酮酸或草酰乙酸）和一种还原剂（即 NADH 或 NADPH）。从 l-蛋氨酸生成 NA 的酶活性在 pH 约为 9 时最高。这种生物合成活性受到缺铁胁迫的显著诱导。从 S-腺苷-l-蛋氨酸合成 NA 比从 l-蛋氨酸更有效。根据此处报道的无细胞系统的结果，我们提出了一种修订后的 MAs 生物合成途径。
