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OXSM / 3-oxoacyl-[acyl-carrier-protein] synthase, mitochondrial · IHC design guide
Design Immunohistochemistry for OXSM
Plan paraffin-section OXSM IHC around granular cytoplasmic staining (HPA tissue IHC) and the protein’s mitochondrial location (UniProt). Start the IHC-validated antibody at 2–5 μg/ml (datasheet A12866-1), using adrenal glandular cells as a high-staining reference and skeletal myocytes as a low-staining reference (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
OXSM Immunohistochemistry Experimental Design Guide
Expected localisation, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before staining
| Expected localisation | Granular cytoplasm (HPA tissue IHC); mitochondrion (UniProt) | |
| Staining pattern | Granular cytoplasmic staining across tissues (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A12866-1) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | None in HPA (detected in all 45 tissues); use no-primary + isotype controls |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A12866-1) | |
| Caveat | Skeletal myocytes show low staining (HPA tissue IHC) | |
| Regulation | Widely expressed (UniProt) | |
| Isoform / epitope | 2 isoforms; mature chain begins at residue 28 (UniProt) |
Section 1
Recommended OXSM IHC & IF Protocols
The catalog antibody protocol uses EDTA pH 8.0 retrieval (datasheet A12866-1). Published OXSM IHC protocols cover glioma (PMC12474845) and colon cancer tissue microarrays (PMC12890678).
| Sample | Paraffin-embedded human Colorectal adenocarcinoma tissue; fixative not specified (datasheet A12866-1) |
| Fixation | Image fixative and duration unreported (datasheet A12866-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet A12866-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A12866-1) |
| Primary antibody | Rabbit anti-OXSM, 2-5 μg/ml (datasheet A12866-1) |
| Primary incubation | Overnight at 4 °C (datasheet A12866-1) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A12866-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | OXSM-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression with a granular pattern in all tissues. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet A12866-1); sodium citrate retrieval is a published alternative for colon cancer tissue microarrays (PMC12890678).
Section 2
What Is the Expected OXSM Staining Pattern?
OXSM is a mitochondrial protein with no transmembrane segment (UniProt Q9NWU1 topology). In paraffin section IHC, expect granular cytoplasmic staining across many tissues, including glandular cells and cortical glial cells (HPA tissue IHC: Enhanced reliability; high staining in listed cells). HPA reports high consistency between antibody staining and RNA expression (HPA tissue IHC: Enhanced reliability).
| Granular cytoplasmic staining in colon or duodenal glandular cells. | This matches the reported high glandular staining and all-tissue granular profile (HPA tissue IHC). Assess intensity against the tissue's own cell types; broad expression means a positive result need not be confined to one gland (HPA tissue IHC: low tissue specificity). |
| Predominantly nuclear or sharply membranous staining, without a granular cytoplasmic component. | This does not fit mitochondrial localisation or the reported tissue pattern (UniProt Q9NWU1 subcellular location; HPA tissue IHC). Treat it as possible nonspecific staining or a detection artefact; review controls before scoring cells as OXSM-positive (general IHC practice). |
| Strong staining limited to smooth muscle cells, myocytes, adipocytes or marrow hematopoietic cells. | HPA reports low IHC staining in those cell groups (HPA tissue IHC). Strong isolated staining warrants a specificity check for cross-reactivity or endogenous detection activity (general IHC practice). Low HPA skeletal-muscle IHC staining should not be overridden by UniProt's higher tissue-expression statement (HPA tissue IHC; UniProt Q9NWU1 tissue specificity). |
| Uniform color across extracellular space, nuclei and cytoplasm, obscuring granules. | A field-wide haze cannot establish the reported granular cytoplasmic pattern (HPA tissue IHC). Check background with a no-primary control, then review blocking, washes and chromogen development as general IHC variables (general IHC practice). |
| No interpretable signal in colon glandular cells or cerebral-cortex glial cells. | Both are reported as high-staining cell populations (HPA tissue IHC). A negative result there calls for checking tissue quality, retrieval and detection controls before interpreting an experimental sample as OXSM-negative (general IHC practice); HPA supplies no OXSM-specific fixation-sensitivity claim. |
💡Expected OXSM appearanceCall a result positive when cells show granular cytoplasmic staining, potentially strong in listed glandular cells or cortical glia (HPA tissue IHC: high); isolated nuclear or membrane-only color is suspect (UniProt Q9NWU1 subcellular location; HPA tissue IHC).
| Compartment and processing | OXSM is mitochondrial and lacks a transmembrane segment (UniProt Q9NWU1 topology). Its annotated chain spans residues 28–459 (UniProt Q9NWU1 processing). Use the granular cytoplasmic IHC pattern as the slide-level expectation (HPA tissue IHC); routine chromogenic IHC does not resolve individual mitochondria (general IHC practice). |
| Tissue and cell selection | HPA reports high staining in glandular cells of adrenal gland, appendix, breast, colon, duodenum and endometrium, and in cervical squamous cells and cortical glia (HPA tissue IHC). Smooth muscle cells, myocytes, adipocytes and marrow hematopoietic cells are listed as low (HPA tissue IHC). Compare the relevant cell population, rather than whole-section color (general IHC practice). |
| Antibody evidence | Target-specific fixation effects are not established by the supplied assay evidence. Verify with a matched IHC source before attributing a result to fixation. |
| Isoforms, modifications and retrieval | UniProt lists 2 isoforms and modified residues, including acetyllysine and succinyllysine annotations (UniProt Q9NWU1). The supplied records do not map an IHC epitope to either isoform or modification. If staining is weak, assess retrieval using assay controls (general IHC practice); no OXSM-specific retrieval or fixation effect is established here. |
| IF/ICC Q: What localisation should a separate IF assay assess? | A: HPA reports mitochondria as supported and cytosol as uncertain, with ICC-IF images in A-431, U-251MG and U2OS (HPA subcellular). UniProt identifies mitochondria (UniProt Q9NWU1 subcellular location). This localisation evidence informs interpretation; the IF/ICC assay belongs to its own guide page. |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected high-staining glandular cells show no signal. | An assay or tissue-control failure is possible; high staining is reported for several glandular populations (HPA tissue IHC). | Verify a known-positive section and detection controls, then assess retrieval and primary-antibody conditions as general IHC variables (general IHC practice). Do not infer an OXSM-specific fixation defect from this result. |
| Signal is mainly nuclear or follows the plasma membrane. | That distribution conflicts with mitochondrial localisation and granular cytoplasmic tissue staining (UniProt Q9NWU1; HPA tissue IHC). | Check a no-primary control and inspect whether the color tracks tissue edges or background; interpret compartment assignment only after those controls are acceptable (general IHC practice). |
| Strong color appears in cells HPA lists as low-staining. | The cell-type distribution may reflect cross-reactivity or endogenous detection activity (HPA tissue IHC; general IHC practice). | Compare adjacent expected-positive cells, include a no-primary control, and check endogenous enzyme blocking when using chromogenic enzyme detection (general IHC practice). |
| Diffuse color hides the granular pattern. | Background from incomplete blocking, washing or overdevelopment can obscure cellular detail (general IHC practice); it cannot confirm the HPA granular pattern (HPA tissue IHC). | Review the no-primary section, blocking and wash steps, and chromogen development time; score only cells whose cytoplasm remains interpretable (general IHC practice). |
| Skeletal-muscle myocytes stain weakly despite an expectation of abundant OXSM. | HPA lists low myocyte IHC staining, while UniProt describes higher skeletal-muscle expression (HPA tissue IHC; UniProt Q9NWU1 tissue specificity). These observations address different readouts. | Use the HPA myocyte staining level for slide interpretation and include an HPA high-staining cell population to check assay performance (HPA tissue IHC; general IHC practice). |
| The positive control stains unevenly across the section. | Uneven section handling or detection may affect apparent intensity (general IHC practice); the supplied sources provide no target-specific fixation-effect evidence. | Inspect section integrity and control uniformity, then repeat or adjust routine IHC handling if needed (general IHC practice). Avoid assigning regional loss specifically to OXSM biology without supporting evidence. |
Experiment evidence
IHC & IF images showing OXSM staining
A12866-1 · IHCIHC analysis of OXSM using anti-OXSM antibody (A12866-1). OXSM was detected in a paraffin-embedded section of human Colorectal adenocarcinom
A12866-1 · IHCIHC analysis of OXSM using anti-OXSM antibody (A12866-1). OXSM was detected in a paraffin-embedded section of human endometrial adenocarcino
A12866-1 · IFIF analysis of OXSM using anti-OXSM antibody (A12866-1). OXSM was detected in an immunocytochemical section of PC-3 cells. Enzyme antigen re
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000151093-OXSM/tissue/cerebral+cortex#imid_5696260
HPA · DuodenumHuman Protein Atlas IHC, Duodenum. Source: https://www.proteinatlas.org/ENSG00000151093-OXSM/tissue/duodenum#imid_5696177
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000151093-OXSM/tissue/colon#imid_5696186
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000151093-OXSM/tissue/liver#imid_5696187
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA021293; green = OXSM, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA021293; green = OXSM, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for OXSM IHC & IF
🧪Run adrenal gland first and score its glandular cells for OXSM staining (HPA: High in adrenal gland glandular cells). HPA detects OXSM in all 45 scored tissues, so there is no supported negative tissue; use no-primary and isotype controls, and treat any unstained nonglandular cells on the positive slide as a background reference rather than a proven biological negative (HPA: no negative rows).
Positive control tissue: Adrenal gland (Glandular cells, HPA High)
Negative control tissue: None in HPA: OXSM is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show OXSM in A-431, U-251MG, U2OS, with annotated localisation: Mitochondria (supported), Cytosol (uncertain) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only slide, a rabbit IgG isotype control matched to the primary antibody’s format, and an OXSM knockout or validated peptide-block control (caption: rabbit anti-OXSM primary). Check endogenous peroxidase signal in adrenal tissue before interpreting DAB staining (caption: peroxidase secondary and DAB detection).
⚠️Feasibility: A target-specific fixation window and fixation effect are unreported, and the selected A12866-1 paraffin-section caption does not state the fixative (caption: fixative not stated). That caption uses heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required under other conditions (caption: EDTA retrieval). ICC-IF images exist for A-431, U-251MG and U2OS, with supported mitochondrial localization and uncertain cytosolic localization; the supplied evidence does not establish whether IF or frozen sections are easier than paraffin IHC (HPA: subcellular summary and ICC-IF image cell lines).
HPA tissue IHC evidence for OXSM
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — High consistency between antibody staining and RNA expression data.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Appendix | Glandular cells | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Cerebral cortex | Glial cells | High | Protein (IHC) | HPA → |
| Cervix | Squamous epithelial cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: OXSM is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced OXSM IHC Tips
Troubleshoot chromogenic OXSM staining in paraffin sections by checking retrieval, cellular pattern, controls and scoring before interpreting differences between samples.
Which retrieval condition should I try first for OXSM in paraffin sections?
Start with heat-mediated antigen retrieval in EDTA buffer at pH 8.0 for the catalog antibody (datasheet A12866-1). The selected paraffin-section image used this condition before overnight incubation at 4°C with 2 μg/ml antibody (caption A12866-1). If staining is weak, compare retrieval duration on serial sections while holding antibody concentration and DAB development constant; excessive heating can damage tissue morphology (standard IHC practice). Judge improvement by a reproducible granular cytoplasmic pattern, rather than stronger diffuse color, because that pattern is reported across tissues (HPA tissue IHC). Record the retrieval temperature and duration so the comparison can be repeated (standard IHC practice).
How should I handle fixation when OXSM staining varies between sections?
Target-specific sensitivity to fixation is unknown: the selected OXSM image identifies a paraffin section but does not state its fixative (caption A12866-1). Compare sections with documented, matched fixation and processing histories, and record fixation duration before changing retrieval or antibody concentration (standard IHC practice). On adjacent sections, hold EDTA at pH 8.0 and the 2 μg/ml antibody incubation constant while assessing morphology and staining (datasheet A12866-1; caption A12866-1). Variable preservation can confound an IHC comparison, so use internal tissue landmarks and process comparison sections together (standard IHC practice). Do not assign a target-specific fixation effect from OXSM topology or reported tissue patterns (UniProt Q9NWU1 topology; HPA tissue IHC).
What staining pattern should count as plausible OXSM localisation?
Expect granular cytoplasmic staining in paraffin tissue sections, consistent with the reported tissue pattern (HPA tissue IHC). OXSM is annotated as mitochondrial (UniProt Q9NWU1 subcellular location), while the subcellular imaging summary supports mitochondria and marks cytosol as uncertain (HPA subcellular). Score the granules within identifiable cells and compare their distribution with adjacent, morphologically intact cells; diffuse nuclear color alone would not match that evidence (HPA tissue IHC; standard IHC practice). The protein has no annotated transmembrane segment, so a crisp plasma-membrane outline deserves investigation rather than automatic acceptance (UniProt Q9NWU1 topology). Check the same pattern across serial sections before calling a small stained focus positive (standard IHC practice).
Could OXSM isoforms or epitope accessibility explain discordant IHC staining?
OXSM has 2 annotated isoforms, but the supplied antibody evidence does not map the recognized epitope or establish isoform coverage (UniProt Q9NWU1 isoforms; caption A12866-1). The annotated mature chain spans residues 28–459, and the ketosynthase family domain spans 41–458 (UniProt Q9NWU1 processing; domains). Acetylation and succinylation are annotated at selected residues, including alternative modifications at 109 and 174; their effect on this antibody's staining is unknown (UniProt Q9NWU1 modified residues). If staining disagrees with another assay, obtain the immunogen or epitope information and compare matched sections under the same retrieval conditions before attributing the difference to an isoform or modification (standard IHC practice).
How can I check OXSM localisation by IF alongside this chromogenic IHC result?
Use IF as a separate localisation check, because the selected antibody evidence describes chromogenic staining in a paraffin section with DAB (caption A12866-1). Multiplex OXSM with a marker for the expected cell population, such as an epithelial marker when examining glandular cells, and inspect whether OXSM signal falls within those cells (HPA tissue IHC; standard IF practice). Choose a fluorophore and acquisition channel after checking tissue autofluorescence, and include single-color controls to assess bleed-through (standard IF practice). Because OXSM is intracellular and mitochondrial with no annotated transmembrane segment, test permeabilisation for access to an intracellular epitope; its exact epitope and membrane-facing side are unreported (UniProt Q9NWU1 topology and subcellular location; standard IF practice).
How do I reduce diffuse DAB background without losing OXSM granules?
Begin by comparing a no-primary control with the test section, using identical secondary detection and DAB exposure to identify detection-system color (standard IHC practice). Include a peroxidase block, check washing and blocking, and shorten chromogen development if color accumulates broadly (standard IHC practice). The selected image used 10% goat serum blocking, 2 μg/ml primary antibody overnight at 4°C, and a peroxidase-conjugated secondary for 30 minutes at 37°C (caption A12866-1). Preserve the granular cytoplasmic pattern reported for OXSM when adjusting conditions; uniformly stained nuclei or tissue edges warrant scrutiny (HPA tissue IHC; standard IHC practice). Change one condition at a time and compare matched sections (standard IHC practice).
How should I score OXSM IHC across samples with different cell composition? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and analysis area before scoring, then record the percentage of positive cells and staining intensity within that population (standard IHC practice). An H-score can combine the percentages at intensity grades 0–3; keep thresholds, counterstain and DAB development consistent across sections (standard IHC practice). Alternatively, report positive-cell density per mm² of viable tissue and normalize to the number or area of the relevant cells, rather than total section area (standard IHC practice). OXSM shows granular cytoplasmic expression across tissues, with differing reported levels among cell populations, so document which cells enter the denominator (HPA tissue IHC). Exclude folds, damaged edges and necrotic areas by a prespecified rule (standard IHC practice).
When should I doubt an apparent OXSM-positive IHC result?
Give most weight to reproducible granular cytoplasmic staining in intact cells, the pattern reported for OXSM in tissue IHC (HPA tissue IHC). Compare the stained cell population with the section's morphology: reported high staining includes colon glandular cells, whereas skeletal-muscle myocytes are listed at a low level (HPA tissue IHC). Nuclear-only signal, a sharp cell-surface outline, staining confined to tissue edges or necrotic material, and color persisting without primary antibody all merit investigation (UniProt Q9NWU1 topology; HPA tissue IHC; standard IHC practice). Check a no-primary control for endogenous peroxidase or detection background, then repeat on a well-preserved adjacent section before assigning a biological difference (standard IHC practice).
Boster reagents
Best OXSM / 3-oxoacyl-[acyl-carrier-protein] synthase, mitochondrial IHC Antibodies
A12866-1 has IHC images from human paraffin sections and an IF image from PC-3 cells (catalog image captions). Human and rat are listed as reactive species (catalog reactivity).
Real IHC data
Anti-OXSM Antibody ®
Cat # A12866-1
A12866-1 has IHC images from human paraffin sections of colorectal, endometrial, esophageal, and liver cancers (A12866-1 IHC captions). Its IF image shows PC-3 cells (A12866-1 IF caption).
Which to pick: Choose A12866-1 for paraffin-section IHC: its human tissue captions document EDTA retrieval at pH 8.0 and 2 μg/ml primary antibody (A12866-1 IHC captions); the fixative is unreported (A12866-1 IHC captions). Choose the same SKU for IF/ICC in cells, supported by its PC-3 IF image and listed IF/ICC applications (A12866-1 IF caption; catalog applications). For rat samples, the catalog lists rat reactivity, while the supplied IHC and IF images show human tissue and PC-3 cells, respectively (catalog reactivity; A12866-1 image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9NWU1 (OXSM_HUMAN, 3-oxoacyl-[acyl-carrier-protein] synthase, mitochondrial).
- Human Protein Atlas. OXSM tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. OXSM subcellular location (ICC-IF): Localized to the cytosol and mitochondria..
- Human Protein Atlas. OXSM antibody validation summary (3 antibodies).
- Disulfidptosis OXSM serves as a potential prognostic biomarker and correlates with immune infiltrates in glioma. Discover oncology 2025 — PMC12474845.
- Disulfidptosis-related genes signature predicts prognosis and immune microenvironment in colon cancer. Frontiers in molecular biosciences 2026 — PMC12890678.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:16641997 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for OXSM (3-oxoacyl-[acyl-carrier-protein] synthase, mitochondrial). Expected localisation Granular cytoplasm (HPA tissue IHC); mitochondrion (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A12866-1). Validated IHC antibody: A12866-1 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative None in HPA (detected in all 45 tissues); use no-primary + isotype controls. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human Colorectal adenocarcinoma tissue; fixative not specified (datasheet A12866-1); 2. Fixation: Image fixative and duration unreported (datasheet A12866-1); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat retrieval: EDTA pH 8.0 (datasheet A12866-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A12866-1); 8. Primary antibody: Rabbit anti-OXSM, 2-5 μg/ml (datasheet A12866-1); 9. Primary incubation: Overnight at 4 °C (datasheet A12866-1). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A12866-1); Caveat: Skeletal myocytes show low staining (HPA tissue IHC); Isoform / epitope: 2 isoforms; mature chain begins at residue 28 (UniProt); Regulation: Widely expressed (UniProt). Evidence: UniProt Q9NWU1, HPA tissue IHC · Enhanced, HPA ICC-IF · cytosol and mitochondria., Datasheet A12866-1, PMC12474845, PMC12890678. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/OXSM/immunohistochemistry-ihc-guide.