1) The document describes work to synthesize and separate methylated versions of the peptide octreotide using HPLC. 2) Methylated peptide standards were synthesized to represent likely mono-methylation products of octreotide. 3) An HPLC method was developed and optimized to achieve baseline separation of the methylated peptide standards. This would allow identification of radioactive methylation products from subsequent radiochemistry experiments.

1. SEPARATION OF METHYLATED PEPTIDIC STANDARDS BY HPLC Erin Saucke-Lacelle Supervisors: Dr. Ralf Schirrmacher Dr. Chris Wilds

5. PRECURSOR PEPTIDE Peptide Sequence: Trp-Cys-Gly-D-Phe-Cys-Tyr-D-Trp-Lys-Thr-Cys-Thr OCTREOTIDE (KIMCHI)

6. POSSIBLE METHYLATION PRODUCTS

12. Gradient from 100% H 2 0 to 100% ACN over 40 min

13. Chromolith Column, 100 x 4.6mm

14. flow 1.4 mL/min

15. Agilent 1200 series multi-wavelength UV detector

16. Raytest gamma detector

19. Synthesized peptides to represent most likely monomethylated standards

20. This HPLC method sufficiently separates standards in order to clearly identify radiochemistry methylation results

22. Isolate and identify products

23. Hopefully, alkylation will occur at Cys residue to give a single labeled product

25. R. Maurer, B. H. Gaehwiler, H. H. Buescher, R. C. Hill, D. Roemer, Proc. Natl. Acad. Sci. 79(15) , 4815-7 (1982)

27. Dr. Esther Schirrmacher

28. Dr. Chris Wilds

29. Ryuhjin Angela Ahn

30. Grant from Natural Sciences and Engineering Research Council of Canada