A variety of methds exist to determine the sequence or amino acid composition of a peptide. Typically, the peptide is purified using reverse phase HPLC, SDS-PAGE, or PVDF blotting prior to analysis. Methods for analysis include:

• Edman degradation (N-terminal sequencing) - (N-TS) - A technique invented by Pehr Victor Edman. The sequence is determined by the sequential treatment of the peptide with phenylisothiocyanate (PITC) which results in the cleavage and derivatization of the N-terminal amino acid. The resulting amino acids are analyzed in the order they are cleaved and the original peptide sequence is deconvoluted.

• C terminal sequencing - (C-TS) - Peptide degradation can be accomplished chemically (the C-terminal carboxyl group is activated as a mixed anhydride and then reacted with isothiocyanate) or enzymatically (using one of several carboxypeptidase enzymes). This method typically requires larger amounts of sample versus N-terminal sequencing.

• internal sequencing - (I-S) - This method is used when the N-terminus or C-terminus is blocked. Alternatively, it can be used if it is not known whether or not the termini are blocked, and the user does not want to take a chance on having a problem

• mass spectrometry - (MS) - de novo peptide sequencing can also be performed using mass spectrometry instrumentation

• amino acid analysis - (AAA) - Peptides are cleaved to their individual amino acids under acidic conditions (e.g., 6 N HCl). The resulting mixture is then quanitified to determine the percentage of each amino acid in the original peptide.

Here is a list of companies with a brief description of the kind of services that they provide.

1. 21st Century Biochemicals - (MS) - including LC/MS and stability studies

2. AIPharma - (N-TS, AAA, MS) - offering GMP protein and peptide characterization, including N-terminal sequencing, amino acid analysis, and mass spectrometry

3. Alberta Peptide Institute - (AAA) - quantitative and qualitative amino acid analysis and peptide/protein sequencing from electroblotted samples

4. Alta Bioscience - (N-TS)

5. Anaspec - peptide standards for sequencing analysis

6. Argo Bioanalytical - (N-TS) - specializing in high-sensitivity Edman protein sequencing

7. Biosynthesis - amino acid analysis and peptide/protein sequencing

8. Cambridge Peptides - (N-TS) - N-terminal sequencing using Edman degradation

9. Commonwealth Biotechnologies - (N-TS, C-TS) - C-terminus sequence analysis by carboxypeptidase Y digestion. Peptide mapping services are also offered.

10. Eurosequence - (N-TS, C-TS, I-S, AAA) - amino acid analysis, peptide/protein sequencing using microsequecing techinques and mass spectrometry. They also offer a GMP amino acid sequencing service which is used for qualification testing during GMP manufacturing.

11. Harvard University Microchemistry and Proteomics Analysis Facility - (N-TS, C-TS, MS) - peptide/protein ID using microcapillary LC-MS/MS on 3D and linear ion traps/ MALDI-TOF and hybrid quadrupole-TOF mass spectrometers

12. The Protein Facility of the Iowa State University Office of Biotechnology - (N-TS)

13. Leeds Protein Sequecing Facility - (N-TS, C-TS)

14. Macromolecular Resources - (N-TS, MS) - MS/MS spectra are collected using MALDI-TOF/TOF for de novo sequencing of peptides

15. Midwest Bio Services - (MS) - protein identification by tandem mass spectrometry using nano-LC/MS/MS with complete sample processing

16. M-Scan - (N-TS, MS, AAA) - located in the UK, Switzerland, US, and Germany. GLP, cGMP, FDA inspected contract laboratory with protein characterisation services

17. Proteome Factory - (N-TS, AAA, MS) - contract research and fee-for-services that include protein identification, sequencing, quantification, and proteomics

18. ProtTech - (MS) - peptide/protein ID by nano-LC-MS/MS sequencing

19. Rocky Mountain Instrumental Laboratories - (MS)

20. SSCI - (N-TS, AAA, MS) - specializing in pre-formulation studies under cGMP conditions including N-terminal sequence analysis, amino acid analysis, MALDI-TOF mass spec, peptide mapping, peptide mass fingerprinting, spectroscopy and aggregation studies.