Observations on the determination of the specific activity of the inorganic phosphate fraction of trichloroacetic acid extracts of liver

Abstract

The accepted technic of precipitating the inorganic P present in tissue extracts as magnesium ammonium phosphate for the detn. of the radioactivity was investigated and shown to be subject to considerable error. The magnitude of this error depends on the bulk of the precipitate and is due to co-precipitation and/or adsorption of organophosphates among which are the adenosine polyphosphates. The errors involved in determining the specific activity were discussed, and it is concluded that the turnover rates of organophosphates as previously detd. are probably lower than the true values. A method was descr. which permits the accurate, and rapid detn. of both the radioactivity and the amt. of P present in the one soln.