BELLIER Jean-Pierre（分子神経科学研究センター）

　Biochemical labeled with radioisotope can be used in enzymatic analysis for the determination of enzymatic activities. In comparison with most conventional techniques (such as photometry, fluorimetry, luminometry, etc …), the use of radioisotope introduces a number of unique concerns which make radiometric techniques tedious to establish and use (choice of the radionuclide, calibration, radiation safety, separation of the metabolites after reaction …).
　Regardless of those issues, radiometric technique is accurate and can considerably increase the sensitivity of the determination. Moreover, since it is nearly possible to radiolabel any kind of molecules, then it is nearly possible to perform any kind of determination.
　For those reasons, radiometric technique has found a huge field of application in enzymatic analysis, becoming a method of choice when sensitivity is an issue or when conventional methods cannot be used.

　This seminar will start with a brief introduction on the theoretical basis for the determination of the enzymatic activity. Then, it will be followed by an overview of the benefits and the difficulties related to the usage of the radiometric technique. Next, in an application example, we will see why to choose and how to set-up a radiometric technique to measure the enzymatic activity of the choline acetyltransferase, the enzyme synthesizing the neurotransmitter acetylcholine. Finally, we will overview general principles to avoid error in estimation of enzymatic activity, including procedures to optimize the assay and to survey interference and specificity.