Identification, Purification, and Molecular Cloning of N-1-Naphthylphthalmic Acid-Binding Plasma Membrane-Associated Aminopeptidases from Arabidopsis

摘要: Polar transport of the plant hormone auxin is regulated at cellular level by inhibition efflux from a plasma membrane (PM) carrier. Binding inhibitor N-1-naphthylphthalamic acid (NPA) to regulatory site associated with carrier has been characterized, but NPA-binding protein(s) have not identified. Experimental disparities between levels high-affinity NPA binding and can be explained presence low-affinity in vivo hydrolysis NPA. In Arabidopsis, colocalization amidase aminopeptidase (AP) activities, artificial β-naphthylamide substrates, saturable displacement AP bestatin suggest that PM APs may involved both hydrolysis. We report purification molecular cloning proteins Arabidopsis. This first plants. were purified gel permeation, anion exchange, affinity chromatography monitored for tyrosine-AP activity. Lower fractions contained two orthologs mammalian signal transduction cell surface-extracellular matrix interactions. AtAPM1 ATAPP1 substrate specificities sensitivities similar their orthologs, temporal spatial expression patterns consistent previous planta histochemical data. Copurifying interact secreted surface wall proline-rich proteins. AtAPP1 are encoded single genes. vitro translation products ATAPM1 enzymatic activities those native