PEPotec SRM Custom Peptide Libraries

Thermo Scientific PEPotec SRM Peptide Libraries provide fully synthetic, crude peptides customized for the development of mid- to high-throughput selected reaction monitoring (SRM) and multiple reaction monitoring (MRM) assays in quantitative mass spectrometry (MS) workflows.

Custom SRM Peptide Library specifications

Peptide length 6-25* amino acids
Manufacturing scale ≥0.1 mg
Purity options Crude (as synthesized)
Formulation Suspended in 0.1% TFA in 50% (v/v) acetonitrile/water
Production time 3-4 weeks
Modifications Variety of modifications and labels, including heavy amino acids (isotope-labeled)
C-terminal residue Lysine or Arginine
Counterion Trifluoroacetic acid (TFA)
Delivery Format Peptides are provided in individual 2-D barcoded tubes in 96-tube plates

* Please inquire about longer peptide lengths and manufacturing scale.

Available PEPotec SRM Peptide Library grades

  Grade 1
Fast and easy
Grade 2
Greater analysis
Grade 3
Maximum assurance
SRM Plus SRM HPLC >70% pure
Quality Control (QC) MS check of 5% of peptides MS check of 100% of peptides MS check and analysis of 100% of peptides MS check of 5% of peptides and high throughput purification of 100% of peptides MS check and HPLC analysis of 100% of peptides
Purity Crude Crude Crude ~70% Guaranteed purity of >70%
Peptide Resynthesis Not provided Not provided One resynthesis One re-synthesis One re-synthesis
Difficult peptide Failed synthesis policy You pay for entire set of peptides ordered You only pay for peptides successfully synthesized in the requested library You only pay for peptides successfully synthesized in the request library You only pay for peptides successfully synthesized in the request library You only pay for peptides successfully synthesized in the request library
Included documentation Peptide Amount Peptide Amount Peptide Amount and MS Spectra Peptide Amount and MS Spectra Peptide Amount and MS Spectra
Minimum order 24 peptides 4 peptides 4 peptides 4 peptides 4 peptides

PEPotec SRM Peptide optional heavy amino acids

Amino acid Code Mass difference Isotope Isotopic enrichment
Alanine A +4 Da U-13C3, 15N >99%
Arginine R +10 Da U-13C6, 15N4 >99%
Isoleucine I +7 Da U-13C6, 15N >99%
Leucine L +7 Da U-13C6, 15N >99%
Lysine K +8 Da U-13C6, 15N2 >99%
Phenylalanine F +10 Da U-13C9, 15N >99%
Proline P +6 Da U-13C5, 15N >99%
Valine V +6 Da U-13C5, 15N >99%

† Other amino acids on request.

PEPotec SRM Peptide optional modifications

Available with all grades on a per-peptide basis**

  • C-terminal heavy labeling at R or K
  • Internal heavy labeling at A,R,I,L,K,F,P, or V
  • Alternative heavy amino acid at C-term
  • Alternative light amino acid at C-term
  • Phosphorylation at 1–3 sites
  • All cysteines protected by carbamidomethylation (CAM)
  • Diglycine ubiquitination motif on lysine [Lys(GG)]
  • Methionine sulfoxide [Met(O)]
  • Acetylation at side chain of lysine [Lys(Ac)]
  • Methylation at side chain of lysine [Lys(Me)] and arginine [Arg(Me)]
  • Dimethylation at side chain of lysine [Lys(Me)2]
  • 3-chloro-tyrosine
  • Hydroxyproline (Hyp)
  • Isoaspartic acid
  • Formylation at C-term
  • Carboxymethylcysteine (CMC) at cysteine

** Others available on request.

Frequently asked questions

Q. What is the shelf life of a peptide?

A. The shelf life is >24 months at -20°C for lyophilized peptides protected by argon in the original non open container. This is sequence dependent and it may be shorter for some sequences.

Q. Why is PEPotec SRM of higher quality than most competitors?

A. We are synthesizing our PEPotec using the solid phase Fmoc synthesis on resin. Most of our competitors use the spot technology providing poor quality peptides above 15 amino acids.

Q. How many peptide syntheses typically fail?

For peptide synthesis ~2.4% of the peptides submitted, due to difficult sequence were unable to be synthesized. Most of our competitors announce on their web site 5%.

Q. What peptide parameters are influenced by amino acid composition?

A. The ability to synthesize the peptide and its solubility, stability, and overall charge are discussed in the Protein Biology Learning Center under the Peptide Design.

Q. What information is needed to obtain an accurate quote?

A. All the information required to get an accurate quote is included in the Quote Request form.

Q. What is the difference between SRM, MRM and PRM?

A. SRM (Simultaneous Reaction Monitoring) and MRM (Multiple Reaction Monitoring) is the terminology to describe targeted MS quantitation. SRM and MRM quantitation are typically performed on triple quadrupole instruments. PRM (Parallel Reaction Monitoring) is a new technique described by Dr. Josh Coon and Dr. Bruno Domon. PRM is used for the MS quantitation performed on Q-Exactive instruments (e.g. Orbitrap instrumentation).

Custom SRM Peptide Library specifications

Peptide length 6-25* amino acids
Manufacturing scale ≥0.1 mg
Purity options Crude (as synthesized)
Formulation Suspended in 0.1% TFA in 50% (v/v) acetonitrile/water
Production time 3-4 weeks
Modifications Variety of modifications and labels, including heavy amino acids (isotope-labeled)
C-terminal residue Lysine or Arginine
Counterion Trifluoroacetic acid (TFA)
Delivery Format Peptides are provided in individual 2-D barcoded tubes in 96-tube plates

* Please inquire about longer peptide lengths and manufacturing scale.

Available PEPotec SRM Peptide Library grades

  Grade 1
Fast and easy
Grade 2
Greater analysis
Grade 3
Maximum assurance
SRM Plus SRM HPLC >70% pure
Quality Control (QC) MS check of 5% of peptides MS check of 100% of peptides MS check and analysis of 100% of peptides MS check of 5% of peptides and high throughput purification of 100% of peptides MS check and HPLC analysis of 100% of peptides
Purity Crude Crude Crude ~70% Guaranteed purity of >70%
Peptide Resynthesis Not provided Not provided One resynthesis One re-synthesis One re-synthesis
Difficult peptide Failed synthesis policy You pay for entire set of peptides ordered You only pay for peptides successfully synthesized in the requested library You only pay for peptides successfully synthesized in the request library You only pay for peptides successfully synthesized in the request library You only pay for peptides successfully synthesized in the request library
Included documentation Peptide Amount Peptide Amount Peptide Amount and MS Spectra Peptide Amount and MS Spectra Peptide Amount and MS Spectra
Minimum order 24 peptides 4 peptides 4 peptides 4 peptides 4 peptides

PEPotec SRM Peptide optional heavy amino acids

Amino acid Code Mass difference Isotope Isotopic enrichment
Alanine A +4 Da U-13C3, 15N >99%
Arginine R +10 Da U-13C6, 15N4 >99%
Isoleucine I +7 Da U-13C6, 15N >99%
Leucine L +7 Da U-13C6, 15N >99%
Lysine K +8 Da U-13C6, 15N2 >99%
Phenylalanine F +10 Da U-13C9, 15N >99%
Proline P +6 Da U-13C5, 15N >99%
Valine V +6 Da U-13C5, 15N >99%

† Other amino acids on request.

PEPotec SRM Peptide optional modifications

Available with all grades on a per-peptide basis**

  • C-terminal heavy labeling at R or K
  • Internal heavy labeling at A,R,I,L,K,F,P, or V
  • Alternative heavy amino acid at C-term
  • Alternative light amino acid at C-term
  • Phosphorylation at 1–3 sites
  • All cysteines protected by carbamidomethylation (CAM)
  • Diglycine ubiquitination motif on lysine [Lys(GG)]
  • Methionine sulfoxide [Met(O)]
  • Acetylation at side chain of lysine [Lys(Ac)]
  • Methylation at side chain of lysine [Lys(Me)] and arginine [Arg(Me)]
  • Dimethylation at side chain of lysine [Lys(Me)2]
  • 3-chloro-tyrosine
  • Hydroxyproline (Hyp)
  • Isoaspartic acid
  • Formylation at C-term
  • Carboxymethylcysteine (CMC) at cysteine

** Others available on request.

Frequently asked questions

Q. What is the shelf life of a peptide?

A. The shelf life is >24 months at -20°C for lyophilized peptides protected by argon in the original non open container. This is sequence dependent and it may be shorter for some sequences.

Q. Why is PEPotec SRM of higher quality than most competitors?

A. We are synthesizing our PEPotec using the solid phase Fmoc synthesis on resin. Most of our competitors use the spot technology providing poor quality peptides above 15 amino acids.

Q. How many peptide syntheses typically fail?

For peptide synthesis ~2.4% of the peptides submitted, due to difficult sequence were unable to be synthesized. Most of our competitors announce on their web site 5%.

Q. What peptide parameters are influenced by amino acid composition?

A. The ability to synthesize the peptide and its solubility, stability, and overall charge are discussed in the Protein Biology Learning Center under the Peptide Design.

Q. What information is needed to obtain an accurate quote?

A. All the information required to get an accurate quote is included in the Quote Request form.

Q. What is the difference between SRM, MRM and PRM?

A. SRM (Simultaneous Reaction Monitoring) and MRM (Multiple Reaction Monitoring) is the terminology to describe targeted MS quantitation. SRM and MRM quantitation are typically performed on triple quadrupole instruments. PRM (Parallel Reaction Monitoring) is a new technique described by Dr. Josh Coon and Dr. Bruno Domon. PRM is used for the MS quantitation performed on Q-Exactive instruments (e.g. Orbitrap instrumentation).