Protein dotMETRIC™ Assay

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SKU: 786-20-XX Category:
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Rapidly, mix 1µl protein sample with the supplied Dilution Buffer and apply 1µl of the solution to the test strip by point-of-contact capillary action. Under the assay’s specific buffer conditions the protein enters into the matrix of the test strip, binds and saturates as protein diffuses in a circular manner. Develop the test strip in approximately 5 minutes. A circular protein spot is produced. The diameter of the spot is proportional to the concentration. By measuring the diameter of the spots with the Protein dotMETRIC™ scale you can easily determine concentration of protein (See Figure). No expensive spectrophotometers or cuvettes required.

For increased reproducibility and test reliability the Protein dotMETRIC™ kits are supplied with an optional Spot Application Device. The Spot Application Device allows application of samples using fixed volume capillary tips and simplifies the task of applying the protein solution. The Spot Application Device simplifies the application of one or more samples as well as improves reliability of results.
Known concentrations of gelatin, BSA, avidin, alcohol dehydrogenase (yeast) and thyroglobulin were assayed with Protein dotMETRIC™ protein assay and the assay showed no protein-to-protein variation. Spot formation is not dependent on the amino acid composition of protein and therefore the Protein dotMETRIC™ assay is independent of protein-to-protein variation.
The assay is unaffected by the presence of common laboratory agents, such as reducing agents, chelating agents, detergents, amines, sugars, chaotropes, salts and other common laboratory agents. The Protein dotMETRIC™ assay is compatible with sample loading buffers and is ideal for confirming the amount of protein loaded on polyacrylamide gels.
When protein concentration falls below a level where the diameters of protein spots are no longer large enough to be measured with the Protein dotMETRIC™ scale, the assay kit uses an entirely new strategy for the determination of protein concentration, called Dilution to the Limit of Detection, or the DLD™ Protocol.
When a protein solution is serially diluted and spotted onto the test strip, eventually a dilution is reached beyond which the protein spots are not visible; i.e., the dilution has reached the limit of detection (DLD™). The dilution factor required to reach the limit of detection is used for the determination of protein concentration (See figure 1 below).
  • Spot Application Device (Cat. # 786-63): For use with Protein dotMETRIC™ protein assay. Simplifies the application of one or more samples and improves reliability of results. See figure 2 below.
  • Application Glass Capillary Tips (Cat. # 786-23): 1µl Application glass capillary tips for Protein dotMETRIC™ Protein assay, for use with Spot Application device. Simplifies the application of one or more samples as well as improves reliability of results.
  • Sample Application (pipette) Tips (Cat. # 786-64): For use with Protein dotMETRIC™ protein assay, 1-10µl pipettor tips to be used with standard laboratory pipettes.
  • Developing Trays (Cat. # 786-24): Trays for developing test strips for Protein dotMETRIC™ protein assay.



  • Sample Economy: Use as little as 1µl of sample.
  • Rapid Assay: Takes 8-10 minutes and can assay as little as 2ng BSA.
  • No Protein-to-Protein Variation: dotMETRIC™ assay is independent of protein-to-protein variation.
  • Resistant to Detergents, Reducing Agents & Other Laboratory Agents
  • Versatile Protein Assay: Because of no protein-to-protein variation and tolerance to a wide variety of common laboratory agents, Protein dotMETRIC™ is a versatile protein assay.



  • For rapid estimation of protein concentration.
  • For determination of protein concentration in cellular fractions, tissue & cell lysates and chromatography purification fractions.
  • For protein samples containing common laboratory agents, such as reducing agents (ß-mercaptoethanol, DTT), chelating agents, detergents, amines, sugars and many other agents.
  • To determine protein concentration in gel loading (SDS-PAGE) sample buffers.
  • When limited amount of sample is available for analysis; requires only 1µl protein sample.



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