The L-tyrosine:2-oxoglutarate aminotransferase atrD and the atromentin synthetase atrA catalyze consecutive steps to turn over L-tyrosine into atromentin, which represents the generic precursor molecule for the entire terphenylquinone and pulvinic acid family of pigments, which are widely distributed secondary metabolites in homobasidiomycetes (PubMed:18805498). The first step is catalyzed by atrD which converts L-tyrosine in to 4-hydroxyphenylpyruvate (4-HPP) (PubMed:18805498). Adenylation of two 4-HPP monomers by the atrA adenylation (A) domain, ester bond formation between monomers and atrA, and symmetric C-C-bond formation between two monomers by atrA leads to atromentin (PubMed:18805498). 2-oxoglutarate + L-tyrosine = 3-(4-hydroxyphenyl)pyruvate + L-glutamate Optimum pH is 9.0. Optimum temperature is 37 degrees Celsius. Secondary metabolite biosynthesis. Atromentin has been shown to induce caspase-3 and poly (ADP-ribose) polymerase (PARP) in human leukemia U937 cells (PubMed:19809251). It has also anticoagulant activity (PubMed:5862512). Moreover, atromentin has antimicrobial activity (PubMed:6541963). It acts especially as an inhibitor of FabK, the enoyl-acyl carrier protein (ACP) reductase of S.pneumoniae (PubMed:17323650). Belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family.