APPLICATION NOTE 54

Cambridge Isotope Laboratories, Inc.
isotope.com

Targeted MRM Screening of U-13C
Lipid Yeast Extracts for Robust
Lipidomics Applications
Andrew J. Percy1, Nyasha Munjoma2, David Heywood2,
Lee A. Gethings2, Krista Backiel1
1. Cambridge Isotope Laboratories, Inc. Tewksbury, MA USA
2. Waters Corporation, Manchester UK

Highlights•	Crude lipid yeast extracts (U-13C and unlabeled) comprise
100s of fatty acids and lipids•	Extracts afford broad application potential (e.g., quality
control, credentialing, quantification)•	Targeted methods, results, and applications for the U-13C
lipid yeast extract are described• Methodologies are rapid (8-12 min) and simple to execute

Introduction
Fatty acids (FAs) and lipids are important biological compounds
that are essential to the regulation and control of cellular functions(e.g., membrane structure, signal transduction, apoptosis) andmetabolic pathways (e.g., fatty acid oxidation, ketone bodysynthesis, lipolysis).1 These biomolecules are also functionally
important to an organism’s energy production and storage.
Qualitative / quantitative analysis of these molecular species is acontinual aim of lipidomics research. A driving factor is to better
understand their underlying pathophysiology, as well as to identify
new biomarkers (e.g., cardiovascular disease, diabetes, cancer) or
diagnose existing ones toward improved precision / personalized
medicine.2-4
Regardless of the research objective(s), a growing numberof lipidomics methods utilize hyphenated analytical systems

comprising a separation dimension (e.g., reversed-phaseliquid chromatography, RPLC; hydrophilic interaction liquid
chromatography, HILIC) and a mass spectrometer (operated
in different acquisition modes e.g., multiple reaction monitoringor MRM).5 Critical to the qualitative/quantitative analysis is theincorporation of stable isotope-labeled standards. Among thebenefits, their use helps determine an assay’s effectiveness(i.e., process efficiency), improve measurement precision,and enhance quantitative accuracy.
In this work, we qualified a condensed panel of stable isotopelabeled FAs / lipids in U-13C crude lipid yeast extracts (CIL catalog no.
L-ISO1) on robust, high-throughput, analytical platforms (i.e., RPLCand HILIC-MRM/MS). The verification results of this extract analyses
are presented here along with a discussion of its potential use indifferent types of MS lipidomics applications.

Materials and Methods
Chemicals and Reagents
All reagents were of the highest available grade, and solventswere LC-MS grade. The test samples were U-13C lipid yeast
extracts (~4 × 108 Pichia pastoris cells, ~3 mg dry weight) that were
supplied by CIL (catalog no. L-ISO1) and originally manufactured
by ISOtopic Solutions (Vienna, Austria). While not the focus of thisarticle, unlabeled lipid yeast extracts (CIL catalog no. L-ISO1-UNL)
were similarly supplied and analyzed. The U-13C extracts have 99%
chemical / isotopic purity and were stored in their dried-down form
at -80ºC (light protected) until use.

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Solution Preparation
The U-13C lipid yeast extracts (n = 3) were reconstituted in 1 mL isopropanol (IPA) before a high-speed vortex and brief centrifuge. Note thatalternate solvents (e.g., methyl tert-butyl ether) and volumes (e.g., 200 µL to 2 mL) for dissolution are possible. The solutions were diluted
further in IPA to varying degrees yielding three concentration levels of standard mixes for each extract replicate. These were stored at 4°C
until analysis.
Chromatographic Separation Methods
Analyte separations were performed by RPLC or HILIC using the Waters columns listed below:• RPLC: ACQUITY™ Premier CSH™ C18 (100 × 2.1 mm, 1.7 µm, 130 Å)• HILIC: ACQUITY Premier UPLC BEH Amide (100 × 2.1 mm, 1.7 µm, 130 Å)
These were contained within an ACQUITY Ultra Performance LC™ I-Class Plus system (Waters). The column was maintained at 55°C
(for RPLC) or 45°C (for HILIC), while the autosampler was at 8°C. Following sample injection (2 µL for ESI+, 4 µL for ESI-), separations
occurred over a solvent gradient (see Tables 1 and 2) at an analytical flow rate (0.4 mL / min for RPLC and 0.6 mL / min for HILIC).
Table 1. RPLC and HILIC gradients.
RPLC

HILIC

Time (min)% Eluent B

Time (min)% Eluent B

0

50

0

0.1

0.5

53

2

20

4

55

5

80

7

65

5.1

0.1

7.5

80

8

0.1

10

99

11

99

12

50

Table 2. Chromatographic mobile phase compositions.
RPLC
Eluent A:

acetonitrile:water (at 3:2 v/v) in 10 mM ammonium acetate

Eluent B:

isopropanol: acetonitrile (at 9:1 v/v) in 10 M ammonium acetate

HILIC
Eluent A:

acetonitrile:water (at 9.5:.5 v/v) in 10 mM ammonium acetate

Eluent B:

acetonitrile:water (at 1:1 v/v) in 10 mM ammonium acetate

MS / MS Parameters and Conditions
The chromatographic column (RPLC or HILIC) was coupled to a Xevo™ TQ-XS mass spectrometer (Waters) via a UniSpray ion source.
This source was operated in the positive and negative ionization mode, with data acquired by scheduled MRM. The general MS and specific
MRM settings are outlined in Tables 3 and 4, respectively. Ultra-high-purity nitrogen served as the carrier gas throughout. Note that other
instruments (e.g., Xevo G2-XS QTof, SYNAPT™ XS) and operative modes (e.g., data-dependent acquisition, parallel reaction monitoring)are possible. The consideration to bear is that the acquisition parameters should first be optimized. In practice, this should be empiricallymeasured using a diluted yeast extract (U-13C or unlabeled) as the MS infusion solution.

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Table 3. General acquisition parameters for MRM analysis of the diluted extract samples on a Xevo TQ-XS.
Parameter

Value

Capillary voltage

2.8 kV (ESI+) and 1.9 kV (ESI-)

Source temperature

120°C

Desolvation temperature

500°C

Desolvation gas flow

1000 L / hCone gas flow

150 L / hNebulizer gas

7.0 barCollision gas flow

0.13 L / h

Ion guide offset 1

3.0 V

Ion guide offset 2

0.3 V

Q1/Q3 resolution

unit / unit

Table 4. Specific acquisition parameters for scheduled MRM analysis of a condensed set of FAs / lipids measured by targeted MRM/MS
on a Xevo TQ-XS. The ions tabulated are U-13C (unlabeled additionally shown for reference) with negative ESI highlighted blue.
Abbreviations: CE – collision energy; CV – cone voltage.
Analyte (Fatty Acid Level)

AdductAC 16:1
Cer d34:1 (d18:1/16:0)
Cer d36:1 (d18:1/18:0)
CL 72:6
DG 34:1 (16:0/18:1)
DG 36:3 (18:1/18:2)
FA 18:2
HexCer t36:2 (t18:1/18:1)
LPC 16:1
LPC 18:1
LPE 18:2
LPE 18:3
PA 34:1 (16:0/18:1)
PA 36:1 (18:0/18:1)
PC 34:1 (16:0/18:1)
PC 36:5 (18:2/18:3)
PE 34:1 (16:0/18:1)
PE 36:4 (18:1/18:3)
PG 34:1 (16:0/18:1)
PG 34:2 (16:1/18:1)
PI 34:2 (16:0/18:2)
PI 36:1 (18:0/18:1)
PS 36:1 (18:0/18:1)
PS 36:2 (18:1/18:1)
TG 50:1 (16:0/16:0/18:1)
TG 54:1 (18:0/18:1/18:0)

M+H
M+H
M+H
M-H
M+NH4
M+NH4
M-H
M+H
M+H
M+H
M+H
M+H
M-H
M-H
M+H
M+H
M-H
M-H
M-H
M-H
M-H
M-H
M-H
M-H
M+NH4
M+NH4

U-13C
Precursor m/z
Product m/z
423.44
88.00
572.61
282.40602.72282.401533.27
1533.27649.72332.30675.73355.40297.26297.26784.72298.40518.38189.10548.49189.10501.38355.40499.38353.40710.62271.20740.63299.20802.69189.10824.70189.10755.63299.20779.64299.20787.63299.20785.63269.20876.64297.30908.75301.30830.64301.30828.64299.20903.97586.60963.74644.70Unlabeled
Precursor m/z
Product m/z
400.3684.99
538.50264.30566.60264.301452.00
1452.00
612.60313.30636.60337.30279.20279.20742.58280.30494.30184.10522.40184.10478.30337.30476.30335.30673.50255.30701.50281.30760.55184.10780.55184.10716.50281.30738.50277.30747.50281.30745.50253.30833.50279.30863.60283.30788.50283.30786.50281.30850.79551.50906.55605.40CE (V) CV (V)
28
30
30
10
20
20
10
30
30
30
20
20
40
40
25
25
31
31
40
40
50
50
42
42
20
20

48
20
20
20
50
50
10
50
10
10
30
30
20
20
40
40
50
50
30
30
50
50
60
60
35
35

Data Analysis
Acquisition and processing were performed with TargetLynx™ software (Ver. 4.2; Waters). Data visualization was conducted in Skyline(https://skyline.ms/skyline.url) where peak selections and integrations were validated manually in the absence of peak smoothing.

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Results and Discussion
Through modification of the Neubauer et al.’s yeast production method,6 U-13C and unlabeled extracts of FAs / lipids were produced.
Table 5 lists the identities of an example set of high abundant FAs / lipids in the lipid yeast extracts.
Table 5. Examples of routinely identified FAs and lipids measured in the lipid yeast extracts from QC evaluations. All FAs and lipids in the
U-13C extracts were verified by comparison to 12C standards and / or HRAM-MS data in combination with their fragmentation patterns.
Note: This list is not finite, as alternate FAs / lipids (e.g., acylcarnitine C4-DC and C5-DC, lysophosphatidylethanolamine or LPE 20:5,
monoglyceride or MG 16:1 and 18:0) have been observed.
Category
Glycerolipids

Class
Diglyceride (DG)

Triglyceride (TG)

Glycerophospholipids

Phosphatidic acid (PA)
Phosphatidylcholine (PC)

Phosphatidylethanolamine (PE)

Phosphatidylglycerol (PG)
Phosphatidylinositol (PI)Phosphatidylserine (PS)
Lysophospholipids
Sphingolipids

Other

Lysophosphatidylcholine (LPC)
Lysophosphatidylethanolamine (LPE)
Ceramide (Cer)
Hexosyl ceramide (HexCer)
Acylcarnitines (AC)Cardiolipin (CL)
Coenzyme (Co)
Fatty acid (FA)Examples (Fatty Acid Level)
34:1 (16:0/18:1)
34:2 (16:1/18:1)
34:4 (16:2/18:2)
36:1 (18:0/18:1)
36:3 (18:1/18:2)
36:4 (18:1/18:3)
50:1 (16:0/16:0/18:1)
50:2 (16:0/18:2/16:0)
50:4 (16:1/16:1/18:2)
50:5 (16:1/16:1/18:3)
52:2 (16:0/18:1/18:1)
52:3 (16:1/18:1/18:1)
52:5 (16:1/18:2/18:2)
52:6 (16:1/18:2/18:3)
54:1 (18:0/18:1/18:0)
54:2 (18:0/18:1/18:1)
54:4 (18:1/18:1/18:2)
54:5 (18:1/18:2/18:2)
54:7 (18:1/18:3/18:3)
54:8 (18:3/18:2/18:3)
34:1 (16:0/18:1)
34:2 (16:0/18:2)
36:1 (18:0/18:1)
36:2 (18:0/18:2)
34:1 (16:0/18:1)
34:2 (16:0/18:2)
34:4 (16:1/18:3)
36:2 (18:0/18:2)
36:4 (18:1/18:3)
36:5 (18:2/18:3)
34:1 (16:0/18:1)
34:2 (16:0/18:2)
36:1 (18:0/18:1)
36:2 (18:0/18:2)
36:4 (18:1/18:3)
36:5 (18:2/18:3)
34:1 (16:0/18:1)
34:2 (16:1/18:1)
34:1 (16:0/18:1)
34:2 (16:0/18:2)
36:2 (18:1/18:1)
34:1 (16:0/18:1)
34:2 (16:0/18:2)
36:1 (18:0/18:1)
36:2 (18:0/18:2)
16:1
18:1
18:2
18:3
18:1
18:2
18:3
d34:1 (d18:1/16:0)
d36:1 (d18:1/18:0)
t36:0 (t18:0/18:0)
t36:2 (t18:1/18:1)
t36:2 (t18:1/18:1)
16:1
72:2
72:6
72:8
72:9
Q8
18:2
18:3

34:3 (16:1/18:2)
36:2 (18:0/18:2)
36:5 (18:2/18:3)
50:3 (16:1/16:1/18:1)
52:1 (18:0/16:0/18:1)
52:4 (18:2/18:2/16:0)
52:7 (18:3/18:3/16:1)
54:3 (18:1/18:1/18:1)
54:6 (18:2/18:2/18:2)
54:9 (18:3/18:3/18:3)
34:3 (16:0/18:3)
36:3 (18:1/18:2)
34:3 (16:0/18:3)
36:3 (18:1/18:2)
36:6 (18:3/18:3)
34:3 (16:0/18:3)
36:3 (18:1/18:2)
36:6 (18:3/18:3)
36:1 (18:0/18:1)
34:3 (16:0/18:3)
36:3 (18:0/18:3)

t34:1 (t18:1/16:0)

The following sections discuss the qualification results of FAs / lipids measured in U-13C lipid yeast extracts by robust, high-throughput,
MS-based methods (e.g., Waters library no. APNT135071759 for RPLC). The analysis was conducted by RPLC-MRM/MS and HILIC-MRM/MS
on a broad panel of FAs / lipids. This included the 87 analytes listed in Table 5, along with additional ones from similar and dissimilar FA / lipid
classes.
RPLC-MRM/MS Analysis
Using a previously developed RPLC-MS/MS method, MRM transitions for a broad panel of U-13C FAs / lipids were theoretically determined.
The results revealed the 87 targets in Table 5 to be measured reproducibly across the extract replicates with commendable signal quality.
Further observed was the measurement of additional FAs / lipids across several classes to the ones ascribed in Table 5 as the QC panel.
Note that equivalent results were found for the unlabeled lipid yeast extracts (data not shown). As an example of the identification results,
Figures 1 and 2 illustrate a representative set of extracted ion chromatograms (XICs) for DGs and PIs measured in the diluted U-13C lipid
yeast extracts by RPLC-MRM/MS.

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Intensity (x106, cps)

DG (16:0/16:0) ▀DG (16:0/16:1)▀
DG (16:0/18:0) ▀DG (16:0/18:1) ▀DG (16:1/18:0) ▀DG (16:1/18:1) ▀DG (16:1/18:2)▀
DG (16:1/18:3) ▀DG (18:0/18:1) ▀DG (18:0/18:2)▀
DG (18:0/18:1) ▀DG (18:0/18:2)▀
DG (18:0/18:2) ▀DG (18:0/18:3) ▀Time (min)Intensity (x106, cps)

Figure 1. Representative XICs of example DGs measured in the diluted U-13C lipid yeast extracts by RPLC-MRM/MS (ACQUITY Premier CSH
C18, Xevo TQ-XS in ESI+). The examples comprise several DGs from the QC panel (e.g., 16:0/18:1, 16:1/18:2, 18:0/18:2), as well as
additional DGs (e.g., 16:0/16:0, 16:1/18:3, 18:2/18:2).

PI (16:0/18:1) ▀PI (16:0/18:2) ▀PI (18:0/18:0) ▀PI (18:0/18:1) ▀PI (18:0/18:3) ▀PI (18:1/18:2) ▀Time (min)Figure 2. Representative XICs of example PIs measured in the diluted U-13C lipid yeast extracts by RPLC-MRM/MS (ACQUITY Premier CSH
C18, Xevo TQ-XS in ESI-). The examples comprise several PIs from the QC panel (e.g., 16:0/18:1, 16:0/18:2, 18:0/18:1) as well as additionalPIs (e.g., 18:0/18:0, 18:0/18:3, 18:1/18:2).
As shown in Figure 2, excellent signal strength and resolution was detected for a collection of PIs that were and were not in the QC panel(Table 5). The expanded compound presence supports broad applications in MS lipidomics (e.g., identification, relative quantification).
Alternate sample preparations and analytical platforms will likely provide further potential for application opportunities through theidentification of additional FAs / lipids.
HILIC-MRM/MS Analysis
In a similar manner to the RPLC-MRM/MS analysis, the U-13C lipid yeast extracts were measured by HILIC-MRM/MS. As was the case with the
RPLC-MRM/MS data, FAs / lipids that were and were not in the QC panel (Table 5) were detected, with comparable results obtained for the
unlabeled lipid yeast extracts (data not shown). Figures 3 and 4 illustrate representative sets of XICs for the PCs and PEs measured in the
diluted U-13C lipid yeast extracts by HILIC-MRM/MS.

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Intensity (x109, cps)

PC (16:0/16:0) ▀PC (16:0/16:1) ▀PC (16:0/18:0) ▀PC (16:0/18:1) ▀PC (16:0/18:2) ▀PC (16:0/20:1) ▀PC (16:0/20:2) ▀PC (16:0/20:3) ▀PC (16:1/18:0) ▀PC (16:1/18:1) ▀PC (16:1/18:2) ▀PC (16:1/18:3) ▀PC (18:0/18:0) ▀PC (18:0/18:1) ▀PC (18:0/18:2) ▀PC (18:1/18:2) ▀PC (18:1/18:3) ▀PC (18:1/20:2) ▀PC (18:1/20:3) ▀PC (18:2/18:2) ▀PC (18:2/18:3) ▀Time (min)Figure 3. Representative XICs of example PCs measured in the diluted U-13C lipid yeast extracts by HILIC-MRM/MS (ACQUITY Premier UPLC
BEH Amide column, Xevo TQ-XS in ESI+). The examples comprise a collection of PCs from the QC panel as well as additional PCs(e.g., 16:1/18:1, 18:0/18:0, 18:1/18:1).

Intensity (x106, cps)

PE (16:0/16:0) ▀PE (16:0/16:1)▀
PE (16:0/18:0) ▀PE (16:0/18:1) ▀PE (16:0/18:2)▀
PE (16:1/18:0) ▀PE (16:1/18:1)▀
PE (16:1/18:2) ▀PE (18:0/18:0) ▀PE (18:0/18:1)▀

PE (18:0/18:2)▀
PE (18:0/18:3) ▀PE (18:1/18:1) ▀PE (18:1/18:2) ▀PE (18:1/18:3) ▀PE (18:2/18:2) ▀PE (18:2/18:3) ▀PE (18:2/18:4) ▀PE (18:3/18:3) ▀Time (min)Figure 4. Representative XICs of example PEs measured in the diluted U-13C lipid yeast extracts by HILIC-MRM/MS (ACQUITY Premier
UPLC BEH Amide column, Xevo TQ-XS in ESI-). The examples comprise a collection of PEs from the QC panel as well as additional PEs(e.g., 18:1/18:1, 16:0/16:0, 18:2/18:4).
Overall, the HILIC-MRM/MS results demonstrated the analyte signals to generally have good intensity and resolution. This demonstrates
the extracts’ utility, with additional FAs / lipids potentially measurable in untargeted MS lipidomics applications using different sample
preparations and analytical platforms.
Utility and Prospective Applications
Applications for the U-13C lipid yeast extract are extensive. One example could be in system suitability testing to determine if an analyticalplatform is fit-for-purpose. Here, performance could be tracked using a subset of the reproducibly identified, U-13C FAs and lipids (see Table5) measured in a matrix-free QC sample. In LC-MS (or -MS/MS) experiments, metrics to monitor include those from the chromatographic(e.g., retention time, peak width and symmetry, capacity factor) and mass spectrometric (e.g., mass accuracy, signal intensity, fragmentation
efficiency) systems.7 Through longitudinal QC monitoring, deviations in data quality relating to deficits (e.g., signal drift or offset, peak tailingor splitting) or issues (e.g., column integrity, mass calibration, fragmentation efficiency) in the LC and /or MS system can be revealed, withcorrective action(s) then queued.
Other example applications include the qualification, relative quantification, and credentialing of the lipidome.9 Qualification andquantification of FAs / lipids in sample measurements can be aided with this labeled extract because the analytes are 13C-enriched. The 13C
isotopes confer exceptional chemical / isotopic stability and analytical reliability. Since the isotopes are not susceptible to back-exchange
and the compounds have identical physicochemical properties to their unlabeled counterparts (i.e., natural or endogenous), the labeled /unlabeled partners will coelute during chromatographic separation aiding enhanced identification confidence and improved quantitative

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accuracy. In credentialing, the U-13C and unlabeled yeast extracts are to be mixed at discrete ratios (e.g., 1:1 and 1:2) before LC-MS analysis.
Please refer to Wang et al.’s methods article for details on executing the credentialing workflow with sample extracts (E. coli used as an
example there).10 This unique credentialing protocol helps pinpoint the features that are derived from true biological analytes, and in turnhelps to benchmark analytical parameters and methods in method development.
The U-13C lipid yeast extract can also be applied to alternate analytical methods. An example involves ion mobility (IM)-MS, which is atechnique lauded for its ability to separate isomers, isobars, and structurally similar analogs. IM-MS is orthogonal to traditional separation
techniques, such as RPLC and HILIC; thus, it conceivably provides an effective means to improve the resolving power and specificity ofanalytes when operated alone or in a two-dimensional manner (e.g., RPLC-IM-MS). The use of IM-MS, therefore, represents an additional
area to which the U-13C lipid extracts can be potentially applied to enhance the identification / quantification depth and breadth.

Conclusions
Given the need for improved standard tools in MS lipidomics, U-13C and unlabeled crude lipid yeast extracts were manufactured under novel,
but strict, batch processes. After QC, these commercially available products were disseminated for verification as part of an inter-lab study.
Here, the extracts were analyzed by RPLC- and HILIC-MRM/MS methods. The purpose of this analysis was to qualitatively verify the QC panelof FAs / lipids and determine if additional FAs / lipids could be readily measured. The results demonstrated complete verification and broader
measurement capability. Overall, applications for these crude lipid yeast extracts can arise in the areas of quality control, credentialing,
identification, and relative quantification. It is the hope that the utilities described here can be capitalized on in the future by researchers
in the MS lipidomics field toward better achieving application objectives.
References
1.	Tracey, T.J.; Steyn, F.J.; Wolvetang, E.J.; et al. 2018. Neuronal lipid metabolism: multiple pathways driving functional outcomes in health and disease. Front Mol Neurosci, 11,
10-34.
2.	Matsushita, Y.; Nakagawa, H.; Koike, K. 2021. Lipid metabolism in oncology: why it matters, how to research, and how to treat. Cancers, 13(3), 474-496.
3.	Cui, M.Y.; Yi, X.; Zhu, D.X.; et al. 2021. Aberrant lipid metabolism reprogramming and immune microenvironment for gastric cancer: a literature review. Transl Cancer Res,
10(8), 3829-3842.
4.	Chhonker, Y.S.; Kanvinde, S.; Ahmad, R.; et al. 2021. Simultaneous quantitation of lipid biomarkers for inflammatory bowel disease using LC-MS/MS. Metabolites, 11(2),106-125.
5.	Harrieder, E.M.; Kretschmer, F.; Böcker, S.; et al. 2022. Current state-of-the-art of separation methods used in LC-MS based metabolomics and lipidomics. J Chromatogr B Analyt
Technol Biomed Life Sci, 1188, 123069-123078.
6.	Neubauer, S.; Haberhauer-Troyer, C.; Klavins, K.; et al. 2012. U-13C cell extract of Pichia pastoris – a powerful tool for evaluation of sample preparation in metabolomics.
J Sep Sci, 35(22), 3091-3105.
7.	Broadhurst, D.; Goodacre, R.; Reinke, S.N.; et al. 2018. Guidelines and considerations for the use of system suitability and quality control samples in mass spectrometry assays
applied in untargeted clinical metabolomic studies. Metabolomics, 14(6), 72-88.
8.	Rampler, E.; Abiead, Y.E.; Schoeny, H.; et al. 2021. Recurrent topics in mass spectrometry-based metabolomics and lipidomics – standardization, coverage, and throughput.
Anal Chem, 93(1), 519-545.
9.	Wang, L.; Naser, F.J.; Spalding, J.L.; et al. 2019. A protocol to compare methods for untargeted metabolomics. Methods Mol Biol, 1862, 1-15.

Related Products
Catalog No.

Description

Unit Size

Metabolites/Vial

ISO1

Metabolite Yeast Extract (U- C, 98%)

1 kit

100s

ISO1-UNL

Metabolite Yeast Extract (unlabeled)

1 kit

100s

13

Note: ISO1-KIT comprises a tube of both ISO1 and ISO1-UNL. Also, all kits are supplied with a document package (i.e., user manual, CoA,SDS, product flyer), which is accessible via a QR code on the product box.

RESEARCH PRODUCTS

Cambridge Isotope Laboratories, Inc.
isotope.com

Please click on the flyer for product-related application
information and isotope.com for pricing.

Metabolite and Lipid
Yeast Extracts
For MS Metabolomics and Lipidomics

Cambridge Isotope Laboratories, Inc. (CIL) is pleased to offer 13C-labeled and unlabeled yeast extracts for use in MS-based
quantitative or profiling studies of various sample types. These extracts have been rigorously characterized by a number ofmethodologies and are amenable to a variety of research uses after simple reconstitution. The components in the extracts span broad
metabolic classes (e.g., amino and organic acids, sugar phosphates, coenzymes, fatty acids and lipids), biochemical pathways (e.g., citrate
and glyoxylate cycle, nucleotide and lipid metabolism), and cellular/molecular processes (e.g., intracellular signaling, immune system, blood
coagulation, lipolysis).

Overview
Catalog No.
ISO1
ISO1-UNL
NEW! ISO1-KIT
NEW! L-ISO1
NEW! L-ISO1-UNL

Uses

Description
Metabolite Yeast Extract (U-13C, 98%)
Metabolite Yeast Extract (unlabeled)
Metabolite Yeast Extract Kit
Crude Lipid Yeast Extract (U-13C, 99%)
Crude Lipid Yeast Extract (unlabeled)• Targeted or untargeted, MS-based analysis• Method and instrument QC• Quantitation• Biomarker discovery and verification

Benefits

Dry extract of Pichia pastoris cells (strain CBS 7435).
Produced by ISOtopic Solutions (isotopic-solutions.com).
Please inquire
for pricing.

• Reduces measurement uncertainty• Improves precision and accuracy• Enhances identification confidence• Decreases development time and cost

Example References
Reiter, A.; Asgari, J.; Wiechert, W.; et al. 2022. Metabolic footprinting of microbial systems
based on comprehensive in silico predictions of MS/MS relevant data. Metabolites, 12(3),257-280.
Zhao, X.; Golic, F.T.; Harrison, B.R,; et al. 2022. The metabolome as a biomarker of aging
in Drosophila melanogaster. Aging Cell, 21(2), e13548.
Rampler, E.; Hermann, G.; Grabmann, G.; et al. 2021. Benchmarking non-targeted
metabolomics using yeast-derived libraries. Metabolites, 11(3), 160-179.
Mairinger, T.; Weiner, T.; Hann, S.; et al. 2020. Selective and accurate quantification of
N-acetylglucosamine in biotechnological cell samples via GC-MS/MS and GC-TOFMS.
Anal Chem, 92(7), 4875-4883.
Galvez, L.; Rusz, M.; Schwaiger-Haber, M.; et al. 2019. Preclinical studies on metal based
anticancer drugs as enabled by integrated metallomics and metabolomics. Metallomics,
11(10), 1716-1728.
Demarest, T.G.; Truong, G.T.D.; Lovett, J.; et al. 2019. Assessment of NAD+ metabolism
in human cell cultures, erythrocytes, cerebrospinal fluid and primate skeletal muscle.
Anal Biochem, 572, 1-8.

Guijas, C.; Montenegro-Burke, J.R.; Domingo-Almenara, X.; et al. 2018. METLIN: A technology
platform for identifying knowns and unknowns. Anal Chem, 90(5), 3156-3164.
Si-Hung, L.; Causon, T.J.; Hann, S. 2017. Comparison of fully wettable RPLC stationary phases
for LC-MS-based cellular metabolomics. Electrophoresis, 38(18), 2287-2295.
Schwaiger, M.; Rampler, E.; Hermann, G.; et al. 2017. Anion-exchange chromatography
coupled to high-resolution mass spectrometry: A powerful tool for merging targeted andnon-targeted metabolomics. Anal Chem, 89(14), 7667-7674.
Ortmayr, K.; Hann, S.; Koellensperger, G. 2015. Complementing reversed-phase selectivity
with porous graphitized carbon to increase the metabolome coverage in an on-line
two-dimensional LC-MS setup for metabolomics. Analyst, 140(10), 3465-3473.
Neubauer, S.; Chu, D.B.; Marx, H.; et al. 2015. LC-MS/MS-based analysis of coenzyme A
and short-chain acyl-coenzyme A thioesters. Anal Bioanal Chem, 407(22), 6681-6688.
Application Note
Percy, A.J.; Munjoma, N.; Heywood, D.; et al. 2022. Targeted MRM screening of U-13C lipid
yeast extracts for robust lipidomics applications (CIL application note #54).

Hermann, G.; Schwaiger, M.; Volejnik, P.; et al. 2018. 13C-labelled yeast as internal standard
for LC-MS/MS and LC high resolution MS-based amino acid quantification in human plasma.
J Pharm Biomed Anal, 155, 329-334.

Cambridge Isotope Laboratories, Inc.
North America: 1.800.322.1174 cilsales@isotope.com | International: +1.978.749.8000 intlsales@isotope.com | fax: 1.978.749.2768 | isotope.com
MET_RSCH_YEAST (10/13/22)
Supersedes all previously published literaturecilsales@isotope.com | intlsales@isotope.com | isotope.com 7

| Application Note 54

Cambridge Isotope Laboratories, Inc.

Please visit isotope.com for a complete list of isotope-labeled compounds.
Research products are distributed and sold worldwide via our extensive network.
CIL’s distributor listing is available at isotope.com.
To request a quotation or place an order:
North America: 1.978.749.8000 | 1.800.322.1174 | cilsales@isotope.com
International: +1.978.749.8000 | intlsales@isotope.com
Fax: 1.978.749.2768 | isotope.com

Cambridge Isotope Laboratories, Inc. 3 Highwood Drive, Tewksbury, MA 01876 USA+1.978.749.8000 | fax: +1.978.749.2768 | 1.800.322.1174 (North America) | isotope.com

App_note_54 (10/13/22)

Supersedes all previously published literature