Radiation Safety
The highly specific binding interaction between antibodies and their unique antigens has been exploited to create sensitive and specific detection systems for proteins. An antibody can be raised and/or purified “against” (i.e. binding to) a…
A method for determining the location of a protein binding site, DNase I Footprinting Analysis involves endonuclease treatment of an end labeled DNA fragment bound to a protein. Limited digestion yields fragments terminating everywhere except…
Working with radioactive isotopes requires diligent attention to safety measures, in order to avoid hazardous exposure(s). Because radioactivity cannot be detected without instrumentation, spills can easily be spread through and even out of the lab…
Radiolabeled materials are often analyzed by chromatography. The original application of liquid scintillation counting to chromatographic techniques was to collect and count discrete fractions. This manner of counting is extremely laborious, and resolution is limited…
Complex radioactive samples are often fractionated on polyacrylamide gels. Analysis of radiolabeled samples in electrophoretic gels follow the same pattern as that on TLC plates. The gel is analyzed as a whole for radioactive bands,…
Samples of animal or plant tissue are rarely thin or small enough to allow for full counting efficiency. Homogenization of such samples will allow them to be dispersed into a cocktail, but processing large numbers…
A common radiotracer technique is to precipitate macromolecules (protein & DNA) with TCA or some other strong denaturant, collect the precipitate on a filter and count it. Often such procedures give variable results, depending upon…
In a typical TLC experiment, the radioactivity is detected at two points: after TLC it is analyzed by autoradiography, to locate radioactive spots. These spots are then scraped off of the plate and counted to…
An aspect of LSC which must be considered in experimental design, is waste disposal. Unlike solid scintillation, LSC adds components to the sample increasing the volume of radioactive material by up to 1000 fold. The…
Another commonly encountered artifact is chemiluminescence. This is caused by any chemical reaction which generates an excited product molecule, which decays to emit light. These reactions generate only a single photon, which may be quenched,…