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- Table of Contents
CTSZ / Cathepsin Z · Western blot design guide
Design a Western Blot for CTSZ
Source-linked CTSZ Western blot protocol options, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-CTSZ WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Evidence assembled September 2026 · For research use; verify linked source records and product datasheet before use
CTSZ Western Blot Experimental Design Guide
Expected bands, source-linked protocol options, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before running
| Expected band | Cleaved fragment; mass unreported | |
| Gel | 12–15% (standard starting point) | |
| Positive control | Adrenal gland (IHC candidate; verify WB) +4 more | |
| Negative control | Adipose tissue (IHC candidate; verify WB) |
Important caveats
Reasons your observed band may differ from the expected size.
| Lead specificity | Cleaved target; verify fragment size for this antibody | |
| PTM | Glycosylated + Cleaved | |
| Caveat | Cleavage-state controls | |
| Gene-set association | MSigDB Hallmark membership | |
| Isoform | 1 isoform(s) |
Section 1
Source-Linked CTSZ Western Blot Protocol Options
The A04256 protocol combines labelled catalog values with standard starting conditions. Published comparisons retain their own sample, reagent and detection scope.
| Sample / lysate | various cells (catalog A04256) |
| Gel % | 12–15% (standard starting point) |
| Load | 20–30 µg total protein per lane; optimize for abundance (standard starting point) |
| Transfer | Standard semi-dry transfer; verify efficiency (standard starting point) |
| Membrane | 0.45 µm PVDF (standard starting point) |
| Blocking | 5% milk or 5% BSA in TBST (standard starting point) |
| Primary antibody | A04256; use the WB datasheet starting dilution (standard starting point) |
| Primary incubation | Overnight at 4 °C (standard starting point) |
| Secondary antibody | Species-matched HRP conjugate at validated dilution (standard starting point) |
| Secondary incubation | 1 h at room temperature (standard starting point) |
| Wash | 3 × 5 min in TBST (standard starting point) |
| Detection | ECL; bracket exposures to avoid saturation (standard starting point) |
Section 2
What Is the Expected CTSZ Western Blot Band Size?
The predicted precursor is 33.9 kDa; cleavage and N-linked glycosylation may affect migration, but no empirical band size or feature-driven shift is demonstrated.
| Band near 33.9 kDa | consistent with the predicted precursor mass, pending identity controls |
| Band below 33.9 kDa | may reflect processing of the signal peptide and propeptide; mature mass is unknown |
| Precursor-sized and smaller bands | may represent precursor and processed CTSZ, if confirmed with state-specific antibodies |
| Band above 33.9 kDa | N-linked glycosylation at Asn184 or Asn224 may contribute; a visible shift is unproven |
💡Expected CTSZ appearanceUniProt predicts a 33.9 kDa precursor; the lead Cleaved-Leu62 antibody recognizes a cleaved state with no supplied band size, so confirm band identity with peptide blocking and a total CTSZ antibody.
| UniProt precursor mass | predicts 33.9 kDa before processing |
| N-linked glycosylation at Asn184 | may increase apparent mass, but no visible shift is established |
| N-linked glycosylation at Asn224 | may increase apparent mass, but no visible shift is established |
| Signal peptide at residues 1–23 | cleavage reduces protein mass relative to the precursor |
| Propeptide at residues 24–61 | processing reduces protein mass relative to the precursor |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | lysosomal CTSZ may be dilute, or the cleaved epitope may be absent | compare lysosome-enriched material and a total CTSZ antibody |
| Band higher than expected | N-linked glycosylation at Asn184 or Asn224 is possible | compare treated and untreated samples after N-glycan removal and verify band identity |
| Band lower than expected | signal peptide and propeptide processing may yield a smaller species | compare total CTSZ and Cleaved-Leu62 antibody signals |
| Broad smear instead of sharp band | heterogeneous N-linked glycosylation is possible but unconfirmed | test N-glycan removal and confirm CTSZ identity |
| Multiple bands | precursor and processed CTSZ species may coexist | compare total and cleavage-specific antibodies and use peptide blocking |
| Weak or no signal | the Cleaved-Leu62 epitope may be scarce | check total CTSZ signal and include a cleavage-positive control |
Experiment evidence
Western blot images showing CTSZ band
A04256 · CTSZ
A04256 · CTSZ
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for CTSZ Western blot
🧪HPA-IHC candidate guidance (verify in WB): For positive controls for CTSZ in Western blot, you can use adrenal gland tissue, which HPA scores High.
Positive control: Adrenal gland (IHC candidate; verify WB)
Negative control: Adipose tissue (IHC candidate; verify WB)
Loading controls: Run GAPDH, β-actin, and a total-protein stain such as Ponceau alongside the samples.
⚠️Feasibility: HPA identifies contrasting tissues, but verify their CTSZ signals by Western blot.
HPA tissue expression evidence for CTSZ
Comprehensive Human Protein Atlas IHC scoring per tissue. Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Higher expression tissues · candidate positive controls from IHC
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | glandular cells | High | Protein (IHC) | HPA → |
| Appendix | glandular cells | High | Protein (IHC) | HPA → |
| Breast | myoepithelial cells | High | Protein (IHC) | HPA → |
| Bronchus | respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Cerebellum | GLUC cells - cytoplasm/membrane | High | Protein (IHC) | HPA → |
Lower expression tissues · IHC evidence, not confirmed WB-negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | adipocytes | Not detected | Protein (IHC) | HPA → |
| Esophagus | squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
| Hippocampus | glial cells | Not detected | Protein (IHC) | HPA → |
| Nasopharynx | respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
| Placenta | decidual cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced CTSZ Western Blot Tips
Deeper troubleshooting and optimisation questions for CTSZ, answered from its protein features.
How should CTSZ band migration be interpreted?
Band shift · Use the separately labelled calculated mass and catalog-observed evidence above. A sequence annotation does not establish an observed migration shift. Verify target identity with orthogonal controls.
Are multiple CTSZ isoforms expected from these features?
Isoforms · The supplied record lists one isoform and no alternative sequence. It gives no basis to assign multiple bands to splice isoforms. Consider processing and glycosylation when interpreting bands, while confirming band identity experimentally.
Where are the CTSZ glycosylation sites?
PTM · UniProt lists N-linked glycosylation at Asn184 and Asn224, using the supplied 303-residue sequence numbering. Check the numbering convention used for any antibody or published construct before comparing sites. These annotations alone do not establish a visible band shift.
Does this guide establish induction of CTSZ?
Induction · No general induction response is established by this guide. A pathway or gene-set association is not evidence of induction in a particular specimen. Verify the relevant treatment and control in a target-specific experiment.
How should transfer be checked for CTSZ?
Transfer · Standard workflow guidance: verify transfer efficiency for the intended target size before interpreting a weak signal. Use total-protein assessment and optimize transfer for the membrane, gel and apparatus; the labelled catalog values take precedence.
How should blocking be optimized?
Blocking · Standard workflow guidance: follow the A04256 datasheet where specified. Otherwise compare 5% milk or 5% BSA in TBST; for a phospho-specific assay start with BSA. Optimize background and specific signal with matched controls.
How should CTSZ bands be quantified?
Quantitation · Choose a consistent band or defined set of bands across samples and report which species was measured. CTSZ is annotated as a zymogen with signal and propeptide segments, so bands may represent different forms. The supplied features do not identify an observed band or establish that every band is CTSZ.
Why might CTSZ run differently from its predicted 33.9 kDa?
Interpretation · The 33.9 kDa prediction refers to the supplied 303-residue sequence. CTSZ has a signal peptide at residues 1–23, a propeptide at 24–61, and two N-linked glycosylation sites. These features could affect the form detected, but the supplied data contain no observed band size or demonstrated shift.
CTSZ is annotated as a zymogen with a signal peptide at 1–23 and a propeptide at 24–61. A band could represent a form retaining or lacking these segments. Identify which form the antibody detects before assigning a band; the features alone do not establish its apparent size.
Potential interpretations include differently processed CTSZ forms or glycosylation-related differences, given its signal peptide, propeptide, and N-linked sites at Asn184 and Asn224. The record does not establish an observed band pattern, so apparent mass alone cannot identify any unexpected band.
The supplied record annotates six disulfide bonds. Record whether samples were prepared under reducing or nonreducing conditions when comparing bands. The annotations do not predict a specific migration pattern or prove that a band difference results from disulfides.
CTSZ is annotated as a zymogen with a signal peptide at 1–23 and a propeptide at 24–61. A band could represent a form retaining or lacking these segments. Identify which form the antibody detects before assigning a band; the features alone do not establish its apparent size.
Potential interpretations include differently processed CTSZ forms or glycosylation-related differences, given its signal peptide, propeptide, and N-linked sites at Asn184 and Asn224. The record does not establish an observed band pattern, so apparent mass alone cannot identify any unexpected band.
The supplied record annotates six disulfide bonds. Record whether samples were prepared under reducing or nonreducing conditions when comparing bands. The annotations do not predict a specific migration pattern or prove that a band difference results from disulfides.
Boster reagents
CTSZ Western Blot Antibodies
Catalog antibodies with Western blot application and product-specific WB images. Evaluate suitability with the reported sample, controls and experimental conditions.
Real WB data
Anti-Cleaved-Cathepsin Z (L62) CTSZ Antibody
Cat # A04256
A04256 is listed for human and monkey reactivity and has a Western blot image described as analysis of various cells. The supplied evidence does not specify the cell types or blot conditions.
Which to pick: A04256 is the only listed CTSZ antibody. It has a Western blot image; check whether its stated human or monkey reactivity fits your sample.
Source: BosterBio CTSZ gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry Q9UBR2.
- Human Protein Atlas. CTSZ tissue expression.
- PMC13224022 — target-verified WB comparison
- PMC12326790 — target-verified WB comparison
- PMC8106142 — target-verified WB comparison