D-dopachrome tautomerase (DDT) is an enzyme that catalyzes the tautomerization and decarboxylation of D-dopachrome to produce 5,6-dihydroxyindole (DHI), a key intermediate in melanin biosynthesis. The enzyme possesses dopachrome isomerase and phenylpyruvate tautomerase activities and functions both in the cytoplasm and extracellular exosomes. DDT regulates inflammatory responses through positive regulation of tumor necrosis factor production and ERK1/2 cascade activation via cytokine receptor binding, while simultaneously exerting negative effects on macrophage chemotaxis. Note: The provided PubMed abstracts exclusively address dichlorodiphenyltrichloroethane (DDT), the persistent organochlorine pesticide, rather than D-dopachrome tautomerase, the protein encoded by the DDT gene. The pesticide literature documents DDT's persistence in human tissues, association with diabetic nephropathy, liver toxicity through ROS-mediated mechanisms, and endocrine-disrupting properties through both estrogen receptor-dependent and independent pathways 12345. However, no abstracts provide information about the biological function, mechanism, disease relevance, or clinical significance of the D-dopachrome tautomerase protein itself. A complete gene function summary requires additional primary literature specifically addressing this enzyme's physiological role.