| Property | Summary |
|---|---|
| Gene name | **SLC25A15** (solute carrier family 25 member 15) (pqac-00000000, pqac-00000005) |
| Aliases | **ORC1**, **ORNT1** (pqac-00000005, pqac-00000009) |
| Protein name | **Mitochondrial ornithine transporter 1** / **ornithine carrier 1 (ORC1)** (pqac-00000001, pqac-00000009) |
| UniProt ID | **Q9Y619** (provided target identity) |
| Chromosomal location | **13q14** / chromosome 13 locus reported for human **SLC25A15** (provided target identity; disease/gene mapping consistent with human SLC25A15 literature in pqac-00000015, pqac-00000020) |
| Protein length | **301 amino acids** (pqac-00000025) |
| Subcellular localization | **Inner mitochondrial membrane**; carrier with N- and C-termini exposed to the cytosolic/intermembrane-space side (pqac-00000023, pqac-00000025) |
| Primary substrates | **L-ornithine, L-citrulline, L-arginine, L-lysine**; transport is stereoselective for the L-forms in ORC1 (pqac-00000004, pqac-00000006) |
| Transport mechanism | **Electroneutral antiport**, classically exchanging **cytosolic ornithine** for **matrix citrulline + H+** in a strict 1:1 mode (pqac-00000001, pqac-00000006, pqac-00000010) |
| Tissue expression | Highest/major expression reported in **liver, pancreas, lung, kidney**; broader tissue expression also noted (pqac-00000005, pqac-00000028, pqac-00000030) |
| Key substrate-binding / mechanistic residues | **E77, R179, E180** directly contribute to substrate binding; **W224** and **R275** help couple binding to conformational change/translocation (pqac-00000004, pqac-00000025, pqac-00000026) |
| Structural class | Member of the **mitochondrial carrier family (SLC25)** with **6 transmembrane α-helices** and tripartite architecture (pqac-00000023, pqac-00000024) |
| Associated disease | **Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome** / ornithine translocase deficiency (pqac-00000009, pqac-00000010, pqac-00000015, pqac-00000000) |
| Paralogues / related compensatory carriers | **ORC2 / SLC25A2**: 87% identical paralogue with lower affinity and broader substrate range; **ORNT3 / SLC25A29**: related basic amino acid carrier that can rescue ornithine metabolism in HHH fibroblasts (pqac-00000029, pqac-00000030, pqac-00000034) |


*Table: This table summarizes the core identity, localization, transport properties, structural determinants, disease relevance, and related paralogues of human SLC25A15/ORC1. It is useful as a compact reference for functional annotation and pathway interpretation.*