DUOX1 is a membrane NADPH oxidase that assembles with DUOXA1 and generates extracellular hydrogen peroxide. Its transmembrane hemes and cytosolic FAD/NADPH-binding machinery conduct electron transfer, while intracellular EF-hand elements mediate calcium regulation. The extracellular N-terminal region has a peroxidase-like fold but lacks the intrinsic peroxidase activity of a conventional mammalian peroxidase. DUOX1-derived peroxide contributes to epithelial defense and redox signaling.
The heme-containing membrane oxidase/dehydrogenase machinery transfers reducing equivalents from NADPH through FAD and hemes to oxygen. The extracellular peroxidase-like domain is a different structural region. Direct biochemical work finds that the isolated human peroxidase-like domain lacks heme binding and intrinsic peroxidase activity; the C. elegans homolog behaves differently. The human NOT-peroxidase annotation is therefore supported, without negating the heme required by the membrane oxidase. High- and low-calcium structures of DUOX1–DUOXA1 establish EF-hand-dependent conformational regulation. The selected horse deletion removes major elements of that regulatory region, making exact-sequence transfer much less secure than ordinary family identification. Hormone synthesis requires coupling peroxide production to separate peroxidases and the appropriate tissue context.
From PMID:33420071(https://pubmed.ncbi.nlm.nih.gov/33420071/):
Dual oxidases (DUOXs) produce hydrogen peroxide by transferring electrons from intracellular NADPH to extracellular oxygen. They are involved in many crucial biological processes and human diseases, especially in thyroid diseases. DUOXs are protein complexes co-assembled from the catalytic DUOX subunits and the auxiliary DUOXA subunits and their activities are regulated by intracellular calcium concentrations.
The exact target is A0A9L0SQG9, not an arbitrary horse record with a matching name. The reproducible paired-sequence analysis records identity, coverage and internal gaps. It supports homology but is not a reciprocal orthology test. Molecular properties are transferred only with the relevant domain, targeting and paralog constraints. The prediction-time sequence is not independently verified.
The following annotation scopes need source-specific follow-up: cell leading edge, cellular response to cytokine stimulus, cuticle development, protein binding, protein heterodimerization activity, regulation of thyroid hormone generation, response to cAMP, response to virus, superoxide anion generation, superoxide-generating NAD(P)H oxidase activity, thyroid hormone generation. Experimental annotations are not removed merely because a cached abstract omits the gene or a specific assay. High-throughput protein-binding rows require their actual partner or complex context before replacement with an informative molecular function.
Research provenance: external Falcon/Edison was attempted with Perplexity fallback. Some requests returned HTTP 429 and fallback returned insufficient-quota HTTP 401; successful external reports are preserved separately. Primary-source manual synthesis is explicitly labeled manual where no external report was available.