J. Biol. Chem., Vol. 256, Issue 22, 11574-11579, 11, 1981
Estimation of protein turnover in soybean leaves using magic angle double cross-polarization nitrogen 15 nuclear magnetic resonance
J Schaefer, TA Skokut, EO Stejskal, RA McKay and JE Varner
Magic angle cross-polarization 15N nuclear magnetic resonance spectra of
intact lyophilized soybean leaves have been obtained at 9.12 MHz. The
leaves were harvested over a 6-week period from 15N-uniformly labeled
plants exposed to 13CO2 for 1 to 7 days. The concentration of 13C-15N
double labels in the main chains of leaf protein was determined
nondestructively by double cross-polarization techniques. Both
incorporation and turnover rates of these double labels were estimated and
together lead to the conclusion that the protein of a mature, fully
expanded soybean leaf is fairly long lived, with a half-life of about 30
days.