The DBT-SAHAJ National Facility at RGCB is in the process of establishing a large number of targeted panels for quantitation of selected groups of metabolites and lipids using mass spectrometry. These targeted panels provide accurate absolute quantitation of a focused group of analytes using available standards.
Targeted metabolomics or lipidomics is a quantitative approach in which a known set of metabolites is quantitated using 13C, 2H or 15N isotope-labeled internal or external reference compounds. The resulting data can then be used as input variables for statistical analysis.
The goal of the facility is to establish a panel of more than 300 lipid molecules/species, which comes under 25 major lipid classes as shown in Table-1.
Table-1. Panels of lipid classes being established for Targeted Lipidomics |
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S.N | Lipid Classes | S.N | Lipid Classes |
1 | GM3 ganglioside (GM) | 14 | Phosphatidylglycerol (PG) |
2 | Sphingomyelin (SM) | 15 | Cholesterol ester (CE) |
3 | Phosphatidylcholine (PC) | 16 | Free cholesterol (COH) |
4 | Alkyl phosphatidylcholine [PC(O)] | 17 | DG |
5 | Phosphatidylcholine plasmalogen [PC(P)] | 18 | TG |
6 | Lysophosphatidylcholine (LPC) | 19 | Carnitines |
7 | Lysoalkylphosphatidylcholine [LPC(O)] | 20 | Fatty acids |
8 | Phosphatidylethanolamine (PE) | 21 | Dihydroceramide (dhCer) |
9 | Alkyl phosphatidylethanolamine [PE(O)] | 22 | Ceramide (Cer) |
10 | Phosphatidylethanolamine plasmalogen [PE(P)] | 23 | Monohexosylceramide (MHC) |
11 | Lysophosphatidylethanolamine (LPE) | 24 | Dihexosylceramide (DHC) |
12 | Phosphatidylinositol (PI) | 25 | Trihexosylceramide (THC) |
13 | Phosphatidylserine (PS) |
At present our panels include 36 lipid molecules, which come under 13 lipid classes and 2 metabolites of one carbon metabolism. The list of the available panel is given in the table-2 and Table-3 below. These panels are being established in our facility to meet the research needs of investigators on a case-by-case basis.
Investigators who are interested in measuring metabolites or lipids not listed below should contact the facility in-charge to discuss the possibilities for establishing a method.
Table – 2. Established Lipid Panels Available for Targeted Lipidomics |
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S. No. | Lipid Class | Molecule / Species | Precursor (m/z) | Product (m/z) | Internal standard (20 pMol) |
1 | Ceramide | C14:0 | 510.6 | 264.249 | C12:0 Ceramide |
2 | C16:0 | 538.7 | 264.249 | C12:0 Ceramide | |
3 | C18:0 | 566.7 | 264.249 | C12:0 Ceramide | |
4 | C18:1 | 564.7 | 264.249 | C12:0 Ceramide | |
5 | C22:0 | 622.9 | 264.249 | C12:0 Ceramide | |
6 | C24:0 | 650.9 | 264.249 | C12:0 Ceramide | |
7 | C24:1 | 648.9 | 264.249 | C12:0 Ceramide | |
8 | C25:0 | 664.9 | 264.249 | C12:0 Ceramide | |
9 | C26:0 | 658.9 | 264.249 | C12:0 Ceramide | |
10 | C26:1 | 642.9 | 264.249 | C12:0 Ceramide | |
11 | Dihydro-ceramide | C16:0 | 540.7 | 266.4 | C12:0 Ceramide |
12 | C18:0 | 568.7 | 266.4 | C12:0 Ceramide | |
13 | C24:1 | 650.9 | 266.4 | C12:0 Ceramide | |
14 | C24:0 | 652.9 | 266.4 | C12:0 Ceramide | |
15 | Ceramide-1-Phosphate | C16:0 | 618.7 | 264.4 | C12:0 Ceramide-1-Phosphate |
16 | C24:0 | 730.9 | 264.4 | C12:0 Ceramide-1-Phosphate | |
17 | Dihydroceramide-1-Phosphate | C12:0 | 564.6 | 266.4 | C12:0 Ceramide-1-Phosphate |
18 | C24:0 | 732.9 | 266.4 | C12:0 Ceramide-1-Phosphate | |
19 | Lactosyl Ceramide | C16:0 | 862.7 | 264.4 | C12:0 Lactosyl(β) Ceramide |
20 | C24:0 | 974.9 | 264.4 | C12:0 Lactosyl(β) Ceramide | |
21 | Glucosyl Ceramide | C16:0 | 700.7 | 264.249 | C12:0 Glucosyl(β) Ceramide |
22 | C18:0 | 728.7 | 264.249 | C12:0 Glucosyl(β) Ceramide | |
23 | C24:1 | 810.9 | 264.249 | C12:0 Glucosyl(β) Ceramide | |
24 | Dihydroglucosyl ceramide | C12:0 | 646.6 | 266.6 | C12:0 Glucosyl(β) Ceramide |
25 | C16:0 | 702.7 | 266.6 | C12:0 Glucosyl(β) Ceramide | |
26 | C18:0 | 730.7 | 266.6 | C12:0 Glucosyl(β) Ceramide | |
27 | C24:0 | 814.9 | 266.6 | C12:0 Glucosyl(β) Ceramide | |
28 | Sphingomyelin | C18:0 | 731.8 | 184.4 | C12:0 Sphingomyelin |
29 | C24:0 | 815.9 | 184.4 | C12:0 Sphingomyelin | |
30 | Dihydrosphingomyelin | C12:0 | 649.7 | 184.4 | C12:0 Sphingomyelin |
31 | C18:0 | 733.8 | 184.4 | C12:0 Sphingomyelin | |
32 | C24:0 | 817.9 | 184.4 | C12:0 Sphingomyelin | |
33 | Sphingosine | C18:1 | 300.4 | 264.4 | C17 Sphingosine |
34 | Sphinganine | C18:0 | 302.4 | 266.4 | C17 Sphinganine |
35 | Sphingosine-1 Phosphate | C18:1 | 380.4 | 264.4 | C17 Sphingosine-1 Phosphate |
36 | Sphinganine-1-Phosphate | C18:0 | 382.4 | 266.4 | C17 Sphinganine-1-Phosphate |
Table – 3. Established Metabolite Panels Available for Targeted Metabolomics |
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Metabolite | Precursor (m/z) | Product (m/z) | Internal standard | |
1 | Methylmalonic acid (MMA) | 117.1 | 73.125 | MMA-D |
117.1 | 55.071 | MMA-D | ||
2 | Homocysteine (Hcy) | 136.043 | 55.883 | Hcy-D |
136.043 | 89.883 | Hcy-D |