A radio-enzymatic method for the estimation of L-leucine-specific radioactivity.
A method is presented for the estimation of L-leucine concentration and radioactivity in biological samples. The sample L-leucine is specifically bound to tRNA and its radioactivity estimated in the presence of either added labelled L-leucine or cold L-leucine (in the same proportion), as well as in the presence of a large excess of cold L-leucine. The latter gave the measurement of non-leucine radioactivity present in the sample. The measurements in the presence and absence of labelled/cold L-leucine allowed the estimation of L-leucine levels and radioactivity by using a simple set of calculations and a standard curve built with known cold L-leucine concentrations in the presence of a fixed known amount of [14C]L-leucine.
Fernández-López
J A
JA
Departament de Bioquímica i Fisiologia, Universitat de Barcelona, Spain.
Latres
E
E
Remesar
X
X
Alemany
M
M
D000409:Alanine / Q000097:blood; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000818:Animals; D002250:Carbon Radioisotopes; D007930:Leucine / Q000032:analysis* / Q000097:blood; D012356:RNA, Transfer, Leu / Q000378:metabolism; D011874:Radiometry / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity
D002250:Carbon Radioisotopes; D012356:RNA, Transfer, Leu; D000604:Amino Acyl-tRNA Synthetases; D007930:Leucine; D000409:Alanine