Amino Acids

CIL offers a broad and diverse array of unlabeled and stable isotope-labeled amino acids. These include free and protected amino acids (for both canonical and noncanonical) as well as mixes and methyl labeling kits. The amino acids are available for different grade material (e.g., research, microbiological and pyrogen tested), with the labeling accessible for different isotopic enrichments and patterns. Applications are directed to proteomic (e.g., free amino acids for metabolic or chemical incorporation, protected amino acids or preloaded resins for solid phase peptide synthesis), metabolomic (e.g., free amino acids for quantitation), metabolism (e.g., free amino acids for isotopic flux analysis) or structural biology studies.

Related Resources

➤ Stable Isotope-Labeled Products for Metabolic Research
➤ Stable Isotope-Labeled Peptide and Protein Reagents/Kits
➤ Stable Isotopes for Biomolecular NMR
➤ Amino Acid Mixtures for Identification and Quantification
➤ Preloaded Resins

Related Categories

➤ Free Amino Acids
➤ Protected Amino Acids
➤ Amino Acid Mixes
➤ Peptide Synthesis Materials

Stable Isotope Standards for Mass Spectrometry

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Isotope Label

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Isotopic Enrichment Range

Grade

Molecular Weight Range

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Free Amino Acids

CIL offers a multitude of unlabeled and isotopically labeled free amino acids for use in MS- or NMR-based metabolomics, proteomics, and structural biology. The amino acids are canonical (e.g., arginine, lysine, phenylalanine) and noncanonical (e.g., beta-alanine, citrulline, ornithine) in grades of research and microbiological/pyrogen tested (MPT). They are available as uniformly or specifically labeled with carbon-13, nitrogen-15, deuterium, and oxygen-18 and are often used as metabolic tracers, internal standards, or NMR probes for structure and dynamics.

SILAC Amino Acids and Sets

CIL offers a myriad of free amino acids (either stable isotope-labeled or unlabeled) for SILAC (i.e., Stable Isotope Labeling by Amino Acids in Cell culture)-MS proteomic studies. The stable isotopes that are to be metabolically incorporated can be conventional (e.g., L-Lys, L-Arg) or unconventional (e.g., L-Azidohomoalanine) depending on the nature of the SILAC study. Quantitation of the standard or newly synthesized proteins is relative and can be performed in a targeted or nontargeted manner.

Visit our SILAC products page for more information on the technique, resources, applications, and FAQs.

99% Enriched Amino Acids

CIL offers a large breadth of highly enriched (i.e., 99%) stable isotope-labeled amino acids for improved accuracy in quantitative MS-based applications. These materials represent the highest isotopically enriched amino acids that are commercially available and offered in their research grade and/or microbiological/pyrogen tested (MPT) form.

Uniformly Labeled Amino Acids

CIL offers an array of uniformly labeled amino acids for use in MS- or NMR-based, metabolomics and proteomics research. The amino acids are canonical (e.g., alanine, leucine, tyrosine) and noncanonical (e.g., beta-alanine, ornithine) in grades of research and microbiological/pyrogen tested (MPT), with the D-labels predominantly at nonexchangeable positions.

Partially Labeled Amino Acids

CIL offers a multitude of partially labeled amino acids and derivatives for use in MS- or NMR-based, metabolomics and proteomics research.  The amino acids are canonical (e.g., histidine, proline, threonine) and non-canonical (e.g., beta-alanine, citrulline, ornithine) in grades of research and microbiological/pyrogen tested (MPT), with the isotope labels of variable type (i.e., 13C, D, 15N, 18O) and position.

Unlabeled Amino Acids

CIL offers a variety of unlabeled amino acids (AAs). These are available in different forms (e.g., in chloride salt form) and material grades (i.e., research and microbial and pyrogen tested, MPT). Listed below are the specifications, availability, and pricing of our unlabeled, free AAs. Please inquire if an alternate, unlabeled AA is desired. For additional information, refer to our Stable Isotope-Labeled Products For Metabolic Research catalog (see Related Resources).

Stable Isotope-Labeled Arginine

CIL offers a broad collection of isotope-enriched, L-arginine (L-Arg) compounds for use in MS- or NMR-based, metabolomics and proteomics research. This list encompasses uniform and partially labeled L-Arg, with the isotopes (13C, D, and/or 15N) at nonexchangeable positions. Please view the availability, pricing, and specifications of our labeled L-Arg offerings and inquire if alternate labeling is required.

Stable Isotope-Labeled Lysine

CIL offers a broad assembly of isotope-enriched, L-lysine (L-Lys) compounds for use in MS- or NMR-based, metabolomics and proteomics research. This list encompasses uniform and partially labeled L-Lys, with the isotopes (13C, D, and/or 15N) at nonexchangeable positions. The material grade is research or microbiological/pyrogen tested (MPT). Please view the availability, pricing, and specifications of our labeled L-Lys offerings and inquire if alternate labeling is required.

Protected Amino Acids

CIL offers a variety of conventional and non-conventional, protected amino acids for solid phase peptide synthesis. The conventional Fmocs/Bocs include L-Lys (e.g., 13C6, 15N2, CNLM-4754-H-PK) and -Arg (e.g., 13C6, 15N4, CNLM-8474-H-PK), while the nonconventionals encompass alternate protected amino acids (e.g., Leu, Ile, Phe, Tyr, Val). Isotopic labeling can be either uniform or partial, with preloaded resins also available to help aid peptide synthesis efforts.

Amino Acid Mixes

To help reduce development time/cost and improve user reproducibility in amino acid analysis, CIL is pleased to offer a number of amino acid (AA) mix options. These are available in their stable isotope-labeled and unlabeled form, with the formulation prepared via gravimetry (e.g., canonical and noncanonical mixes) or by hydrolysis of an algal protein (i.e., “cell free” mixes). The canonical and noncanonical AA mixes are designed for qualification/quantitation exercises in targeted or untargeted MS metabolomics, while the cell-free AA mixes are intended for cell-free protein expression.

Amino Acids, Precursors, and Kits for Methyl Labeling

The use of methyl TROSY techniques, in conjunction with specialized isotopic labeling, have significantly increased the useful molecular weight range available for NMR investigations for the study of large proteins and supramolecular protein complexes. The isotope labeling requirements include protonated methyl groups enriched with 13C in an otherwise perdeuterated molecule. Extensive deuteration is required to reduce T2 relaxation rates to maximize the amount of available magnetization at the start of signal collection. The introduction of 13CH3 groups in a perdeuterated protein sample may be achieved by several methods. For in vivo-based protein expression, the addition of deuterated glucose along with the addition of sufficient quantities of the methyl-containing amino acid(s) to the D2O-based cell culture medium is critical. For cell-free protein expression, the labeled amino acid(s) must be present in the amino acid mix used. 

CIL is proud to offer a variety of 13CH3-labeled deuterated amino acids for use in methyl TROSY experiments. CIL also offers kits for labeling Alanine and ILVA for use in E. coli-based protein expression. In addition, CIL offers a complete line of α-ketoisobutyric and α-ketoisovaleric acids for ILV labeling. In order to increase the signal-to-noise greater than two-fold than what can be achieved using the α-ketoisovaleric acids, CIL also offers Pro-S and Pro-R precursors for valine and leucine for use in E. coli cultures.