XmlmmCIF equivalent: pdbx_nmr_exptl_sample The chemical constituents of each NMR sample. Each sample is identified by a number and each component in the sample is identified by name. XmlmmCIF equivalent: pdbx_nmr_exptl_sample/concentration The concentration value of the component. XmlmmCIF equivalent: pdbx_nmr_exptl_sample/concentration_units The concentration units of the component. XmlmmCIF equivalent: pdbx_nmr_exptl_sample/isotopic_labeling The isotopic composition of each component, 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 labled biomolecule is designated by NA: U-13C; NA-K,H XmlmmCIF equivalent: pdbx_nmr_exptl_sample/solution_id The name (number) of the sample. XmlmmCIF equivalent: pdbx_nmr_exptl_sample/component The name of each component in the sample