Involved in the biosynthesis of tyrosine. Has no prephenate dehydrogenase activity. L-arogenate + NADP(+) = CO2 + L-tyrosine + NADPH NADP increases the apparent affinity for arogenate. The two active domains have the same KM values for arogenate. Amino-acid biosynthesis; L-tyrosine biosynthesis; L-tyrosine from L-arogenate (NADP(+) route): step 1/1. Expressed in roots, stems, leaves, flowers, siliques and seeds. More abundant in seeds. Strongly inhibited by tyrosine. Unlike TYRAAT2, TYRAAT1 is composed of two highly similar and catalytically active peptide domains. No proteolytic cleavage between the two domains. Belongs to the prephenate/arogenate dehydrogenase family.