Help & FAQs: Activity Assays

  • I am studying apoptosis in adherent cells. Can I trypsinize the cells when using Annexin V-FITC to stain the cells?
  • Adherent cells undergoing apoptosis automatically detach from the plate and may not require trypsinization. If there are attached cells, they may be trypsinized without affecting phosphatidylserine (PS).
  • What is R&D Systems doing to reduce its use of packaging from non-renewable resources? R&D Systems should consider re-using styrofoam boxes that are in good condition after delivery.
  • Environmental stewardship is important to R&D Systems and its employees. R&D Systems regularly explores "green" options. First and foremost, the energy expended to ship back the styrofoam box is more detrimental to the environment than having the facility re-use or recycle it. Our stance is to encourage our customers to implement a recycling program locally and we can identify a recycling center for styrofoam nearest your facility if necessary. At R&D Systems we have chosen to reduce the use of styrofoam as much as possible by: Doing extensive stability testing in order to determine which products can be shipped with minimal packaging at ambient temperatures, Converting the use of non-recyclable packaging materials to recyclable plastics, cardboard, or biodegradable materials, and Continuing to investigate alternatives to dry ice shipments, the use of re-usable containers, and gel packs that allow for smaller styrofoam containers. Employees were key to initiating a recycling program at our facilities. Internally, we recycle paper, plastic, cardboard, aluminum, glass, and styrofoam.
  • Are the Caspase Activity Assays quantitative?
  • The Caspase Activity Assays are considered semi-quantitative. The results are best used to determine a fold increase in the Caspase activity in apoptotic cells over that of non-induced cells. The use of a background control (reactions where no cell lysate or substrate is added) is preferred. If this control gives a substantial reading, it should be subtracted from the experimental results prior to calculating the fold increase.
  • How are the Caspase Activity Assays used?
  • Caspase Activity Assays provide a simple and convenient means for assaying protease activity in cell lysates. Upon cleavage of the Caspase-specific peptide substrate, a free reporter molecule can be quantified using a colorimetric or fluorometric microtiter plate reader. Comparison of the signal generated from an apoptotic sample with an uninduced control allows determination of the fold increase in Caspase activity. The level of Caspase activity is directly proportional to the signal detected.
  • Is the cell lysis buffer provided in the Caspase Activity Assay the same for all kits?
  • Yes, the cell lysis buffer supplied is the same for all Caspase Activity Kits. Therefore, cells can be lysed at one time, then used in multiple Caspase Activity Assays.

Annexin V Assays

Caspase Activity Assays

Phosphatase Activity Assays

  • What is R&D Systems doing to reduce its use of packaging from non-renewable resources? R&D Systems should consider re-using styrofoam boxes that are in good condition after delivery.
  • Environmental stewardship is important to R&D Systems and its employees. R&D Systems regularly explores "green" options. First and foremost, the energy expended to ship back the styrofoam box is more detrimental to the environment than having the facility re-use or recycle it. Our stance is to encourage our customers to implement a recycling program locally and we can identify a recycling center for styrofoam nearest your facility if necessary. At R&D Systems we have chosen to reduce the use of styrofoam as much as possible by: Doing extensive stability testing in order to determine which products can be shipped with minimal packaging at ambient temperatures, Converting the use of non-recyclable packaging materials to recyclable plastics, cardboard, or biodegradable materials, and Continuing to investigate alternatives to dry ice shipments, the use of re-usable containers, and gel packs that allow for smaller styrofoam containers. Employees were key to initiating a recycling program at our facilities. Internally, we recycle paper, plastic, cardboard, aluminum, glass, and styrofoam.

TUNEL Assays

  • Why are there two different types of TUNEL detection kits, TdT and TACS-XL, and which should I use?
  • There are two different TUNEL (terminal dUTP Nicked End Labeling) methods for apoptosis detection. The first uses TdT (Terminal deoxynucleotidyl Transferase) to incorporate biotinylated nucleotides into the 3'-OH ends of the DNA fragments. This labeling is optimized by the addition of a cation. The biotinylated nucleotides are then detected by using a streptavidin-HRP-conjugate followed by the substrate.The TACS-XL kits also use TdT to incorporate nucleotides into the 3'-OH ends of the DNA fragments. However, these nucleotides are BrdU-labeled rather than directly biotinylated. A biotinylated anti-BrdU antibody is then used for detection. More efficient incorporation of BrdUTP may result in improved signal-to-noise ratio.