title: Determination of the specific radioactivity of [14C]lactate by enzymatic decarboxylation and 14CO2 collection.
abstract: We present an enzymatic method for the determination of L-[14C]lactate specific radioactivity in complex biological samples containing other radiolabeled compounds. The method is based on the conversion of L-lactate to L-pyruvate by lactate oxidase (no EC number assigned) and the decarboxylation of L-pyruvate by pyruvate oxidase (EC 1.2.3.3). The 14CO2 produced by the enzymatic decarboxylation of pyruvate is quantitatively captured in a CO2 trap and its radioactivity is measured. The method is simple, specific, and precise (2% relative SD). It can be conveniently used for routine multiple determinations of L-[14C]lactate specific radioactivity in tracer metabolic studies. Under specified conditions, the method can also be used to determine the specific radioactivity of L-[14C]pyruvate.
authors.affiliation: Department of Biochemistry and Molecular Biology, Noble Research Center, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
authors.forename: E A
authors.initials: EA
authors.lastname: Lehoux
authors.forename: Z
authors.initials: Z
authors.lastname: Svedruzić
authors.forename: H O
authors.initials: HO
authors.lastname: Spivey
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000032:analysis*; D002250:Carbon Radioisotopes; D003653:Decarboxylation; D007700:Kinetics; D019344:Lactic Acid / Q000032:analysis*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D011771:Pyruvate Oxidase / Q000378:metabolism; D019289:Pyruvic Acid / Q000097:blood; D011817:Rabbits; D015203:Reproducibility of Results; D012588:Scintillation Counting / Q000379:methods; D013696:Temperature; D014020:Tissue Extracts / Q000378:metabolism
chemical_list: D002250:Carbon Radioisotopes; D014020:Tissue Extracts; D002245:Carbon Dioxide; D019344:Lactic Acid; D019289:Pyruvic Acid; D006899:Mixed Function Oxygenases; C021497:lactate 2-monooxygenase; D011771:Pyruvate Oxidase