Simplified analytical methods for the measurement of the synthesis rate of plasma proteins in vivo by the [14C]carbonate method.
We describe a method for obtaining the specific activity of 14C in urea, essential in the measurement of the synthesis rate of a plasma protein in vivo, which is simpler than the original procedure. The principle is the measurement of 14CO2 and NH4+ separately, after incubation with urease. A simple alteration gives samples of 13CO2 for mass spectrometry. The 'recoveries' of 14C and 13C in urea were invariably between 90 and 96% and the CV was 3%.
D000641:Ammonia / Q000032:analysis; D001322:Autoanalysis; D001798:Blood Proteins / Q000096:biosynthesis*; D002245:Carbon Dioxide; D002254:Carbonates / Q000378:metabolism*; D004058:Diffusion; D006801:Humans; D014508:Urea
D001798:Blood Proteins; D002254:Carbonates; D002245:Carbon Dioxide; D000641:Ammonia; D014508:Urea