GO_REF:0000002

GO reference used by source annotation pipeline

Source annotation pipeline provenance for Ugt2a1 annotations including UDP-glycosyltransferase activity.

"GO_REF entry used only to trace source annotation method; biological support was assessed from UniProt and cached literature where available."

GO_REF:0000024

GO reference used by source annotation pipeline

Source annotation pipeline provenance for Ugt2a1 annotations including glucuronosyltransferase activity; membrane.

"GO_REF entry used only to trace source annotation method; biological support was assessed from UniProt and cached literature where available."

GO_REF:0000033

GO reference used by source annotation pipeline

Source annotation pipeline provenance for Ugt2a1 annotations including glucuronosyltransferase activity.

"GO_REF entry used only to trace source annotation method; biological support was assessed from UniProt and cached literature where available."

GO_REF:0000044

GO reference used by source annotation pipeline

Source annotation pipeline provenance for Ugt2a1 annotations including membrane.

"GO_REF entry used only to trace source annotation method; biological support was assessed from UniProt and cached literature where available."

GO_REF:0000120

GO reference used by source annotation pipeline

Source annotation pipeline provenance for Ugt2a1 annotations including glucuronosyltransferase activity.

"GO_REF entry used only to trace source annotation method; biological support was assessed from UniProt and cached literature where available."

GO_REF:0000121

GO reference used by source annotation pipeline

Source annotation pipeline provenance for Ugt2a1 annotations including bile acid metabolic process; glucuronosyltransferase activity; response to symbiont; sensory perception of chemical stimulus; xenobiotic metabolic process.

"GO_REF entry used only to trace source annotation method; biological support was assessed from UniProt and cached literature where available."

PMID:1900353

Odorant signal termination by olfactory UDP glucuronosyl transferase.

For Ugt2a1, this publication was assessed for annotations including glucuronosyltransferase activity; response to toxic substance.

"We report here the molecular cloning and expression of an olfactory-specific UGT. The olfactory enzyme, but not the one in liver microsomes, shows preference for odorants over standard UGT substrates."

PMID:19858781

Human UDP-glucuronosyltransferase UGT2A2: cDNA construction, expression, and functional characterization in comparison with UGT2A1 and UGT2A3.

Source paper of the human UGT2A1 IDA for response to symbiont that is transferred to rat Ugt2a1 by ISO; it characterizes recombinant UGT2A1-2A3 expression and glucuronidation activity and reports no symbiont-response experiment.

"Recombinant UGT2A1, UGT2A2 and UGT2A3 were expressed in baculovirus-infected insect cells and analyzed for glucuronidation activity towards different substrates."

PMID:33765098

The odorant metabolizing enzyme UGT2A1: Immunolocalization and impact of the modulation of its activity on the olfactory response.

Primary rat study using immunohistochemistry and immunogold electron microscopy to localize UGT2A1 in the olfactory epithelium, including at the plasma membrane of the olfactory cilia of olfactory sensory neurons; underlies the GO:0016020 -> GO:0060170 ciliary membrane refinement.

"Immunohistochemistry and immunogold electronic microscopy allowed to localize its expression in the apical part of the sustentacular cells and originally at the plasma membrane of the olfactory cilia of the olfactory sensory neurons, both locations in close vicinity with olfactory receptors."

file:rat/Ugt2a1/Ugt2a1-deep-research-falcon.md

Falcon (Edison Scientific) deep research report: rat Ugt2a1 (UDP-glucuronosyltransferase 2A1, UGT-olf)

Ugt2a1/UGT2A1 is the olfactory UDP-glucuronosyltransferase (UGT-olf), a UGT2A subfamily member enriched in neuro-olfactory tissues, confirming gene identity (UniProt P36510).

"historically termed **UGT-olf/UGTolf**, a member of the UGT2A subfamily enriched in neuro‑olfactory tissues"
UGT2A1 catalyzes glucuronidation, transferring glucuronic acid from UDP-glucuronic acid to nucleophilic acceptors to form more hydrophilic glucuronides, supporting the glucuronosyltransferase molecular function.

"UGT2A1 is a **phase II xenobiotic‑metabolizing enzyme** that catalyzes **glucuronidation**: transfer of glucuronic acid from **UDP‑glucuronic acid (UDPGA)** to small molecules bearing suitable nucleophilic groups (e.g., hydroxyl groups), producing **more hydrophilic glucuronides** that tend to be eliminated more readily."
Glucuronidation by UGT2A1 is part of the olfactory perireceptor process and can contribute to odorant signal termination, supporting the sensory-perception annotations.

"In the olfactory system, such glucuronidation is part of the **perireceptor process**, i.e., local metabolism in the mucus/epithelium that shapes the concentration-time profile of odorants reaching olfactory receptors and can thereby contribute to **signal termination**"
Glucuronidated odorant metabolites fail to stimulate canonical cAMP signaling in olfactory cilia preparations, mechanistically linking UGT2A1 activity to reduced receptor activation.

"olfactory cilia preparations show that **glucuronidated odorant metabolites fail to stimulate canonical cAMP signaling**, consistent with a mechanism by which glucuronidation reduces receptor activation and promotes signal termination"
Immunogold EM localizes UGT2A1 to the plasma membrane of olfactory cilia (in addition to sustentacular-cell ER), supporting membrane localization proximal to odorant receptors.

"Critically, immunogold EM supports localization of UGT2A1 at the **plasma membrane of olfactory cilia**—a location that is unusually proximal to odorant receptors and supports rapid metabolism in the perireceptor space"
UGT2A1 immunolocalizes broadly in the apical olfactory epithelium including sustentacular cells and Bowman's glands/ducts.

"localize UGT2A1 broadly within the olfactory epithelium and especially in the apical region, including **sustentacular cells** and **Bowman’s glands/ducts**"
Ex vivo electroolfactogram experiments show topical β-glucuronidase selectively increases the eugenol but not amyl-acetate response, giving causal in-situ evidence that glucuronidation modulates the olfactory response.

"counteracting UGT activity with topical **β‑glucuronidase** increased the EOG response amplitude to **eugenol** but not to **amyl acetate**, consistent with the interpretation that glucuronidation reduces effective eugenol concentration at receptors"
UGT2A1 substrate scope extends beyond odorants to coumarins, drugs/xenobiotics and steroids (estradiol/testosterone), supporting broader xenobiotic and steroid handling.

"monoterpenoid alcohols** (e.g., geraniol, linalool, borneol, menthol), **coumarins** (e.g., umbelliferone derivatives), **drugs/xenobiotics** (e.g., ibuprofen, valproic acid), and **steroids** (e.g., estradiol/testosterone), supporting a role that extends beyond “odorant-only” metabolism and into broader nasal detoxification and local steroid handling"
Nasal UGTs including UGT2A1 form a protective metabolic barrier reducing local toxicity and xenobiotic delivery to the brain, supporting the xenobiotic metabolic process role.

"frames nasal UGTs (including UGT2A1 expressed in olfactory epithelium) as part of a protective barrier that can reduce local toxicity and potentially limit delivery of xenobiotics to the brain via the nasal route"
Human UGT2A1 is reported highly active in bile-acid glucuronidation, corroborating the bile acid metabolic process annotation as a non-core detoxification role.

"UGT2A1 is described as **highly active in bile-acid glucuronidation**, and it notes characterization of UGT2A1 variants and disease connections (human context)"