Samples are metabolically labeled by isotopes
When samples are labeled by metabolically uptaking stable isotopes (metabolic isotope labeling), describe isotope-labeled compounds in the “isotope_labeled_compound” attributes of BioSample records. Stable isotopes are described in the “isotope” attributes. These attributes are not included in Omics package, so please add these as user-defined ones.
Example:
- isotope_labeled_compound=[U-13C]-glucose
- isotope=13C
In the SDRF rows correspond to the samples, describe the compounds and isotopes in the Characteristics columns.
| Characteristics[isotope_labeled_compound] | Characteristics[isotope] |
| [U-13C]-glucose | 13C |
In this case, isotopes are described at sample-level, so the Labeled Extract Name and Label column values can be left empty.
Extracted metabolites are chemically labeled by isotopes
When samples are chemically labeled by isotopes (chemical isotope labeling), describe isotopes in the SDRF Label column and isotope-labeled compounds in the Comment[isotope_labeled_compound] column.
| Labeled Extract Name | Label | Comment[isotope_labeled_compound] |
| human urine sample 1 12C | 12C | 12C-dansyl chloride |
| human urine pooled sample 13C | 13C | 13C-dansyl chloride |
In this case, isotopes are described at the extract-level, so BioSample records may not contain attributes for isotopes.