Purpose | This immunoassay kit allows for the specific measurement of bovine PFK concentrations in tissue homogenates, serum, and plasma. |
Sample Type | Tissue Homogenate, Serum, Plasma |
Analytical Method | Quantitative |
Detection Method | Colorimetric |
Specificity | This assay recognizes recombinant and natural bovine PFK. |
Cross-Reactivity (Details) | No significant cross-reactivity or interference was observed. |
Characteristics | Bos taurus,Bovine,6-phosphofructokinase, muscle type,Phosphofructo-1-kinase isozyme A,PFK-A,Phosphofructokinase-M,Phosphofructokinase 1,Phosphohexokinase,PFKM,2.7.1.11 |
Components | Reagent (Quantity): Assay plate (1), Standard (2), Sample Diluent (1x20ml), Assay Diluent A (1x10ml), Assay Diluent B (1x10ml), Detection Reagent A 1×120μl Detection Reagent B 1×120μl 2 Wash Buffer(25 x concentrate) (1x30ml), Substrate (1x10ml), Stop Solution (1x10ml) |
Alternative Name | PFKM (PFKM ELISA Kit Abstract) |
Background | Phosphofructokinase (PFK) is a glycolytic enzyme that catalyzes the irreversible transfer of a phosphate from ATP to fructose-6-phosphate. PFK is the key regulatory enzyme for glycolysis. When ATP levels are high in the cell, the cell no longer needs metabolic energy production to occur. In this case, PFK's activity is inhibited by allosteric regulation by ATP itself, closing the valve on the flow of carbohydrates through glycolysis. Recall that allosteric regulators bind to a different site on the enzyme than the active (catalytic) site. Thus ATP binds in two places on PFK: in the active site as a substrate and in the regulatory site as a negative modulator. ATP bound in the regulatory site acts as a modulator by lowering the affinity of PFK for its other substrate, fructose-6-phosphate. |
Pathways | Positive Regulation of Peptide Hormone Secretion, Negative Regulation of Hormone Secretion, Carbohydrate Homeostasis |
Sample Volume | 100 μL |
Plate | Pre-coated |
Protocol | This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for PFK has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any PFK present is bound by the immobilized antibody. An enzyme-linked monoclonal antibody specific for PFK is added to the wells. Following a wash to remove any unbound antibody-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of PFK bound in the initial step. The color development is stopped and the intensity of the color is measured. |
Reagent Preparation |
Bring all reagents to room temperature before use. Wash Buffer - If crystals have formed in the concentrate, warm to room temperature and mix gently until the crystals have completely dissolved. Dilute 20 mL of Wash Buffer Concentrate into deionized or distilled water to prepare 500 mL of Wash Buffer. Standard - Reconstitute the Standard with 1.0 mL of Sample Diluent. This reconstitution produces a stock solution of 100 U/mL. Allow the standard to sit for a minimum of 15 minutes with gentle agitation prior to making serial dilutions. The undiluted standard serves as the high standard (100 U/mL). The Sample Diluent serves as the zero standard (0 U/mL). Detection Reagent A and B - Dilute to the working concentration specified on the vial label using Assay Diluent A and B (1:100), respectively. |
Sample Collection | Tissue homogenates - The preparation of tissue homogenates will vary depending upon tissue type. For this assay, tissue was rinsed with 1X PBS to remove excess blood, homogenized in 20 mL of 1X PBS and stored overnight at ≤ -20 °C. After two freeze-thaw cycles were performed to break the cell membranes, the homogenates were centrifuged for 5 minutes at 5000 x g. Remove the supernate and assay immediately or aliquot and store at ≤ -20 °C. Serum - Use a serum separator tube (SST) and allow samples to clot for 30 minutes before centrifugation for 15 minutes at approximately 1000 x g. Remove serum and assay immediately or aliquot and store samples at -20 °C. Plasma - Collect plasma using EDTA or heparin as an anticoagulant. Centrifuge samples for 15 minutes at 1000 x g at 2 - 8 °C within 30 minutes of collection. Store samples at ≤ -20 °C. Avoid repeated freeze-thaw cycles. Note: Citrate plasma has not been validated for use in this assay. |
Assay Procedure |
3 Allow all reagents to reach room temperature. Arrange and label required number of strips. |
Calculation of Results |
Average the duplicate readings for each standard, control, and sample and subtract the average zero standard optical density. Create a standard curve by reducing the data using computer 4 software capable of generating a four parameter logistic (4-PL) curve-fit. As an alternative, construct a standard curve by plotting the mean absorbance for each standard on the y-axis against the concentration on the x-axis and draw a best fit curve through the points on the graph. The data may be linearized by plotting the log of the PFK concentrations versus the log of the O.D. and the best fit line can be determined by regression analysis. This procedure will produce an adequate but less precise fit of the data. If samples have been diluted, the concentration read from the standard curve must be multiplied by the dilution factor. |
Restrictions | For Research Use only |
Handling Advice |
1. The kit should not be used beyond the expiration date on the kit label. 2. Do not mix or substitute reagents with those from other lots or sources. 3. If samples generate values higher than the highest standard, further dilute the samples with the Assay Diluent and repeat the assay. Any variation in standard diluent, operator, pipetting technique, washing technique,incubation time or temperature, and kit age can cause variation in binding. 4. This assay is designed to eliminate interference by soluble receptors, ligands, binding proteins, and other factors present in biological samples. Until all factors have been tested in the Immunoassay, the possibility of interference cannot be excluded. |
Storage | 4 °C/-20 °C |
Storage Comment | The Standard, Detection Reagent A, Detection Reagent B and the 96-well strip plate should be stored at -20 °C upon being received. The other reagents can be stored at 4 °C. |