Molybdenum (Mo) is one of the less abundant elements in organisms, although essential in the biosynthesis of a prosthetic group named Mo cofactor is a molybdopterin cofactor that acts in the active site as the nitrate molybdoenzymes reductase, aldehyde oxidase, xanthine dehydrogenase and sulfite oxidase. These are critical for nitrate assimilation, the biosynthesis of the phytohormone abscisic acid, the metabolism of purines or sulfite detoxification in plants, animals and microorganisms. The way living things molybdenum is obtained by anion transport inhibitors. While molybdate transport systems such bacterial ATP-binding cassette (ABC) are well understood, was unknown how eukaryotes get molecularly molybdate.

In a recent issue of the journal PNAS, a group of the Department of Biochemistry and Molecular Biology at the University of Cordoba has identified the first eukaryotic molybdate transporter (MOT1) high affinity in the green alga Chlamydomonas. In an election held in the database of the genome of Chlamydomonas, and considering the possible relationship between the transport of sulphate and molybdate, sought possible sulfate transporters whose function had not been established and be different enough to carry another anions such as molybdate.

MOT1 and was isolated, which has two conserved domains with proteins from plants, fungi, algae and bacteria that define a new family of membrane proteins, very little related to plant sulfate transporters SULTR and likely related to the transport of molybdate .
MOT1 functionality was demonstrated by antisense strategy that led to the inactivation of the transport of molybdate and, in turn, the nitrate reductase enzyme. MOT1 was expressed in heterologous Saccharomyces. Transport of molybdate by MOT1 showed the lowest Km described, 6 nM, and was activated in the presence of nitrate.