Mugineic acid is the organic compound consisting of a azetidine group and three carboxylates. A colorless solid, it is a siderophore. More specifically, it is a phytosiderophore, i.e. a plant-produced siderophore. It functions as an iron accumulating agent for barley and other plants. Related phytosiderophores include nicotianamine and avenic acid.
It is biosynthesized from S-methylmethionine. The compound binds metal ions as a hexadentate ligand.
Mugineic acid is a derivative of the nicotianamine, a metal-chelating molecule ubiquitous in higher plants that is produced from three molecules of S-adenosyl methionine by the enzyme nicotianamine synthase.
The immediate precursor is 2'-deoxymugineic acid which is produced from nicotianamine by two reactions, catalysed by nicotianamine aminotransferase and 3-deamino-3-oxonicotianamine reductase.
This is followed by insertion of another hydroxyl group, catalysed by the alpha-ketoglutarate-dependent hydroxylase, 2'-deoxymugineic-acid 2'-dioxygenase:
Mugineic acid is also used as a precursor for the synthesis of other phytosiderophores which play a key role in iron uptake from the soil in graminaceous plants.