   \
A complete description of each NMR sample. Include the concentration \
and concentration units for each component (include buffers, etc.). For each\
component describe the isotopic composition, including the % labeling level,\
if known. \
\
For example:\
1. Uniform (random) labeling with 15N: U-15N\
2. Uniform (random) labeling with 13C, 15N at known labeling\
   levels: U-95% 13C;U-98% 15N\
3. Residue selective labeling: U-95% 15N-Thymine\
4. Site specific labeling: 95% 13C-Ala18,\
5. Natural abundance labeling in an otherwise uniformly labeled\
   biomolecule is designated by NA: U-13C; NA-K,H\
  