Sotoo Nagai

Synthesis of the proposed structure of viscosin

Abstract Two diastereoisomeric d -β-hydroxydecanoyl hexapeptides, ( I ) and ( II ), were synthesized. Although the structure ( I ) has been proposed for viscosin, neither compound was not identical with viscosin. The results therefore suggest that the structure of viscosin must be reinvestigated.

A study of some new and useful n-terminal groups in mass spectrometry of peptides : The use of 3-hydroxyalkanoyl and unsaturated acyl groups☆

Abstract Using model peptides ranging from tri- to dodecapeptides, the utility of several new N-protecting groups, i.e., 3-hydroxyalkanoyl and δ 2 -acyl groups including Oct(OH), Dec(OH), Dod(OH), Myr(OH), Pal(OH), Ste(OH), Δ 2 -Dec, Cro, and Cin, for mass spectrometric sequence analysis were examined. Among these, the Dec(OH)- and Δ 2 -Dec peptide derivatives were found to be superior to the hitherto reported Ac or Dee derivatives, since they gave comparable or sometimes better mass spectra. Particularly the Dec(OH) derivatives yielded two series of sequence peaks (as doublets of 18 mass units apart) ascribable to partial dehydration of the protecting group, the fact which makes the recognition of sequence determining peaks much easier. The Cro and Cin derivatives also gave mass spectra comparable to those of the corresponding Ac or Dec ones, except in a few cases where (Pro-Pro-Gly) 2–4 were model peptides. Permethylation technique can also be effectively applied to the all new acyl derivatives for the mass spectrometric sequence studies.