Analysis of precursor pool labeling kinetics without pool size measurements: A computer-assisted approach

Abstract

A general method is described which permits the correction of macromolecular radioactive labeling data for precursor pool specific activity variation during a labeling period. Measurement of the precursor pool size is made unnecessary. The method involves: 1. (1) Determination of radioactivity in the precursor pool at various times during an extended labeling period. 2. (2) Derivation of a theoretical equation describing the kinetics of labeling of the precursor pool. 3. (3) Computer-assisted fitting of the theoretical equation to the observed labeling data. 4. (4) Use of the parameters obtained from the curve-fitting to calculate the time course of saturation of the precursor pool with exogenous radioactive precursor . The derived saturation curves may be used to correct macromolecular labeling data, on a relative basis, for precursor pool saturation. The method may also be extended to provide absolute specific activity estimates. The application of the method is shown for the UTP and S-adenosyl methionine pools of cultured lymphocytes.