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Description
Human TOP2b ELISA KitProduct Specification Usage Required experimental equipment: 1. Microplate reader (450nm) 2. High precision pipettes and pipette tips: 0. 5 10uL, 5 50uL, 20 200uL, 200 1000uL 3. 37C incubator 4. Distilled or deionized water Sample preparation and requirements: Tissue homogenization: Rinse the tissue with pre chilled PBS (0. 01M, pH 7. 4) to remove residual blood (lysed red blood cells in the homogenate will affect the measurement results). Weigh and
Product Specification
| Usage | Required experimental equipment: 1. Microplate reader (450nm) 2. High-precision pipettes and pipette tips: 0.5-10uL, 5-50uL, 20-200uL, 200-1000uL 3. 37°C incubator 4. Distilled or deionized water Sample preparation and requirements: Tissue homogenization: Rinse the tissue with pre-chilled PBS (0.01M, pH 7.4) to remove residual blood (lysed red blood cells in the homogenate will affect the measurement results). Weigh and mince the tissue. Add the minced tissue to the appropriate volume of PBS (generally a 1:9 weight-to-volume ratio, e.g., 1g of tissue sample to 9mL of PBS. The specific volume can be adjusted according to experimental needs and recorded. It is recommended to add protease inhibitors to the PBS) in a glass homogenizer and grind thoroughly on ice. To further lyse tissue cells, the homogenate can be sonicated or repeatedly frozen and thawed. Finally, centrifuge the homogenate at 5000×g for 5-10 minutes, and collect the supernatant for analysis. Cell Lysis Buffer: Adherent cells should be gently washed with pre-chilled PBS, then trypsinized and harvested by centrifugation at 1000×g for 5 minutes. Suspension cells can be harvested directly by centrifugation. Collected cells should be washed three times with pre-chilled PBS and resuspended in 150-200 μL of PBS per 1×10^6 cells (it is recommended to add protease inhibitors to the PBS; if the cell count is very low, reduce the PBS volume appropriately). Disrupt the cells by repeated freezing and thawing or sonication. Centrifuge the extract at 1500×g for 10 minutes at 2-8°C, and collect the supernatant for analysis. Other biological fluids: Centrifuge at 1000xg for 20 minutes, remove the supernatant, and test. Pre-test preparation: 1. Remove the test kit from the refrigerator 10 minutes in advance and equilibrate to room temperature. 2. Prepare the standard gradient working solution: Add 1 mL of universal diluent to the lyophilized standard, let it stand for 15 minutes to completely dissolve, then gently mix (concentration is 10 ng/mL). Then dilute to the following concentrations: 10 ng/mL, 5 ng/mL, 2.5 ng/mL, 1.25 ng/mL, 0.625 ng/mL, 0.3125 ng/mL, 0.15625 ng/mL, and 0 ng/mL. Serial dilution method: Take seven EP tubes and add 500uL of universal diluent to each. Pipette 500uL of the 10ng/mL standard working solution into the first EP tube and mix thoroughly to make a 5ng/mL standard working solution. Repeat this procedure for subsequent tubes. The last tube serves as a blank well; there is no need to pipette liquid from the penultimate tube. See the figure below for details. 3. Preparation of biotinylated detection antibody working solution: Centrifuge the concentrated biotinylated antibody at 1000×g for 1 minute 15 minutes before use. Dilute the 100× concentrated biotinylated antibody to a 1× working concentration with universal diluent (e.g., 10uL concentrate + 990uL universal diluent). Prepare and use immediately. 4. Prepare the enzyme conjugate working solution: 15 minutes before use, centrifuge the 100× concentrated enzyme conjugate at 1000×g for 1 minute. Dilute the 100× concentrated HRP enzyme conjugate to a 1× working concentration with universal diluent (e.g., 10 μL of concentrate + 990 μL of universal diluent). Prepare immediately. 5. Prepare the 1× wash solution: Dispense 10 mL of 20× wash solution into 190 mL of distilled water (concentrated wash solution removed from the refrigerator may crystallize; this is normal. Allow to stand at room temperature until the crystals have completely dissolved before preparing). Procedure: 1. Remove the desired strips from the aluminum foil bag after equilibration at room temperature for 10 minutes. Seal the remaining strips in a ziplock bag and return to 4°C. 2. Sample addition: Add 100 μL of sample or standard of varying concentrations to the corresponding wells. Add 100 μL of universal diluent to the blank wells. Cover with a film and incubate at 37°C for 60 minutes. (Recommendation: Dilute the sample to be tested at least 1-fold with universal diluent before adding it to the ELISA plate. This will reduce the impact of matrix effects on the test results. The sample concentration should be multiplied by the corresponding dilution factor when calculating the final sample concentration. It is recommended to run replicates for all test samples and standards.) 3. Add Biotinylated Antibody: Remove the ELISA plate and discard the liquid without washing. Add 100 μL of Biotinylated Antibody Working Solution directly to each well. Cover with a film and incubate at 37°C for 60 minutes. 4. Wash: Discard the liquid and add 300 μL of 1x Wash Solution to each well. Let stand for 1 minute, shake off the wash solution, and pat dry on absorbent paper. Repeat this process three times (a plate washer can also be used). 5. Add Enzyme Conjugate Working Solution: Add 100 μL of Enzyme Conjugate Working Solution to each well. Cover with a film and incubate at 37°C for 30 minutes. 6. Washing: Discard the liquid and wash the plate five times as in step 4. 7. Adding substrate: Add 90 μL of substrate (TMB) to each well, cover with a sealing film, and incubate at 37°C in the dark for 15 minutes. 8. Adding stop solution: Remove the ELISA plate and add 50 μL of stop solution directly to each well. Immediately measure the OD value of each well at a wavelength of 450 nm. Calculating experimental results: 1. Calculate the average OD value of the standard and sample replicates and subtract the OD value of the blank well as a correction factor. Plot the standard curve of the four-parameter logistic function on double-logarithmic graph paper, with concentration as the horizontal axis and OD value as the vertical axis. 2. If the sample OD value is higher than the upper limit of the standard curve, dilute the sample appropriately and retest. Multiply the sample concentration by the corresponding dilution factor. |
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| Theory | This kit uses a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA). Sample, standard, biotin-labeled detection antibody, and HRP conjugate are sequentially added to microwells pre-coated with a DNA topoisomerase 2-beta (TOP2b) capture antibody. After incubation and washing, the sample is developed using the substrate TMB. TMB is converted to blue by peroxidase (HRP) catalysis and to yellow by acid. The intensity of the color is positively correlated with the amount of DNA topoisomerase 2-beta (TOP2b) in the sample. The absorbance (OD) is measured at 450 nm using a microplate reader to calculate the sample concentration. | |||||||||||||||||||||||||||||||||
| Source | Human | |||||||||||||||||||||||||||||||||
| Synonym | Human DNA topoisomerase 2-beta ELISA Kit | |||||||||||||||||||||||||||||||||
| Detection Type | Double antibody sandwich method | |||||||||||||||||||||||||||||||||
| Composition |
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| Background | Topoisomerase II beta (TOP2b), also known as DNA topoisomerase 2-β, is an enzyme encoded by the TOP2B gene. It controls and alters the topological state of DNA during transcription. This nuclear enzyme is involved in processes such as chromosome condensation, chromatid segregation, and the relief of torsional stress that occurs during DNA transcription and replication. It catalyzes the transient break and rejoining of two double-stranded DNA strands, allowing the strands to interpenetrate, thereby altering the DNA topology. Two forms of this enzyme exist as possible products of gene duplication events. The gene encoding the beta form is located on chromosome 3, and the alpha form is located on chromosome 17. The gene encoding this enzyme is a target of several anticancer agents, such as mitoxantrone, and various mutations in this gene have been associated with the development of drug resistance. Reduced activity of this enzyme may also play a role in ataxia-telangiectasia. Alternative splicing of this gene produces two transcript variants; however, the second variant has not been fully characterized. | |||||||||||||||||||||||||||||||||
| General Notes | 1. Strictly adhere to the specified incubation time and temperature to ensure accurate results. All reagents must be at room temperature (20-25°C) before use. Refrigerate reagents immediately after use. 2. Improper plate washing may result in inaccurate results. Ensure that all liquid in the wells is aspirated thoroughly before adding substrate. Do not allow the wells to dry out during incubation. 3. Remove any residual liquid and fingerprints from the bottom of the plate, as this will affect the OD value. 4. The substrate developer solution should be colorless or very light in color. Do not use substrate solution that has turned blue. 5. Avoid cross-contamination of reagents and specimens to prevent erroneous results. 6. Avoid direct exposure to strong light during storage and incubation. 7. Do not expose any reagents to bleaching solvents or the strong fumes emitted by bleaching solvents. Any bleaching agent will destroy the biological activity of the reagents in the kit. 8. Do not use expired products, and do not mix components with different product numbers and batches. 9. Recombinant proteins from sources other than the kit may not be compatible with the antibodies in this kit and will not be recognized. 10. If there is a possibility of disease transmission, all samples should be managed properly and samples and testing devices should be handled according to prescribed procedures. |
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| Storage Temp. | If the unopened kit is stored at 4°C, the shelf life is 6 months. | |||||||||||||||||||||||||||||||||
| Test Range | 0.156-10 ng/mL | |||||||||||||||||||||||||||||||||
| Applications | Tissue homogenates, cell lysates, and other biological fluids |
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4.2 ★★★★★
Based on 2025 reviews
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Product Reviews
★★★★★ 3
The dog loves 'em
Color: Blue
The dog loves the balls, and they're the right size for my German Shepherd.
Lost a couple of starts because they're not very durable, the "teeth" are easily broken off, so I am frequently finding "lost teeth" across the house; the squeakers also cannot hold up to my dog's aggressive chewing.
I would still buy them again, as like I said, my dog love 'em!
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Reviewed in the United States on February 15, 2026
★★★★★ 5
Squeaky Spiky Ball (Submitted by OG, The Conqueror)
Size: 4.5 Set of 4
FIVE OUT OF FIVE PAWS. THIS IS THE GREATEST BALL EVER MADE.
My name is OG, and I am a machine built for destruction. For years, I have systematically dismantled every supposed "heavy-duty" toy that dared cross my path. They all fail. They all surrender. But this Spiky Ball? This is my worthy adversary. This is The One.
If you have mighty jaws like mine, this isn’t just a toy—it’s a commitment.
The Aesthetics & Grip (5/5 Jaws)
This ball is bright orange. This is important because it means my Dog-Parent cannot pretend they don't see it when I drop it, covered in drool, directly on their laptop.
The spikes are the best part. They are not soft and pointless like some other toys. These spikes dig right into my gums. It's the perfect texture for a serious, focused chew session. Whether I'm running full-speed or we are locked in a heavy-duty Tug-of-War, those spikes give me the grip I need to apply maximum rotational torque. This ball never slips. It demands I bring my A-game.
The Squeak: My Personal Battle Horn (5/5 Ears)
The volume on this thing is set to LEGENDARY.
They say a quiet dog is a happy dog. WRONG. A loud dog is an active, conquering dog. The squeak is sharp, loud, and glorious. It's not a gentle little peep—it's a declaration. When I hear it, I know the hunt is on. More importantly, when I make it squeak, the humans instantly know I require attention, praise, or the immediate launch of the ball across the yard. It is the best attention-getter I own.
Durability: Unstoppable Force Meets Immovable Object (5/5 Eternal Glory)
This ball is a mystery. It has no discernible weaknesses.
I have performed the full Pitbull Destruction Protocol on this Spiky Ball every day for weeks:
The Gnaw: Prolonged, focused effort to crack the surface—(Failure. It laughs.)
The Shake: Head-whipping force designed to dislocate any internal components—(Failure. The squeak remains.)
The Backyard Abandonment: Left in the rain and dirt for maximum entropy—(Failure. Still orange.)
Most toys are a snack. This toy is a lifetime project. It truly is built for aggressive chewers, and I respect that. It is the only toy that challenges me.
Recommendation
If your dog is serious about their job (chewing, fetching, and being loud), you must buy this. It is the only thing that stands up to my power. It’s loud, it’s spiky, and it’s the best. Go buy it now, and tell them OG sent you.
OG, currently performing a full-body gnaw and shake, signing off.
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Reviewed in the United States on November 11, 2025
★★★★★ 5
Excellent product
Size: 4.5 Set of 4
Our service dog Max (named after Max Muncy 3rd baseman for the Dodgers) lives these balls. They are a sturdy product. Just what we needed for our Max.
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Reviewed in the United States on May 26, 2026
★★★★★ 5
Best squeaky ball for the buck!!
Size: 4.5 Set of 4
my 90lb Pit, LOVES these balls.. and they have been lasting for months!! The squeaker is ok, those are lasting a week or two.. but that's better than average for my guy. At $4 a ball in the 4 pack, it's a great deal for a dog that loves a new toy every month .. I give him one at a time, the 4 pack lasts for many months of fun.
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Reviewed in the United States on March 4, 2026
★★★★★ 5
Durable and Fun!
Size: 4.5 Set of 4
My dog LOVES these balls and barks with excitement when the box arrives. These balls are super durable and a great size that does not allow them to roll under cabinets and sofas.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 28, 2026
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