Dieter Kadereit

Acid-labile protecting groups for the synthesis of lipidated peptides.

Lipidated peptides and their neolipoprotein derivatives are efficient tools for the investigation of biological processes in molecular detail. These compounds are often acid- and base-labile, and their synthesis requires the use of a combination of blocking groups that can be removed under very mild conditions. In this article we demonstrate that the Boc urethane and different trityl-type protecting groups can be cleaved selectively under acidic conditions that are mild enough to be compatible with the demands of lipopeptide synthesis. Thus, the Boc group was cleaved with TMS triflate in the presence of lutidine, and the methyltrityl (Mtt) and the methoxytrityl (Mmt) group were removed with 1% TFA in dichloromethane in the presence of triethylsilane as cation scavenger. Removal of the phenylfluorenyl group was achieved with up to 3% TFA in dichloromethane in the presence of triethylsilane at 0 degrees C. These protecting-group techniques were successfully applied in the synthesis of differently lipidated H-Ras peptides.

Chemoenzymatic Synthesis of Lipidated

This review highlights the use of enzymatic protecting group techniques in the synthesis of lipidated peptides. Lipidated proteins play key roles in signal transduction processes. Moreover, structurally well-defined peptides containing the characteristic linkage region of the peptide backbone with the lipid can provide valuable tools for the study of biological phenomena associated with these protein conjugates. The multifunctionality and pronounced lability towards acids and bases of such compounds render their synthesis a formidable challenge. However, the recent development of enzymatic protection groups provides an efficient access to these sensitive and biologically relevant peptide conjugates under particular mild conditions and with high selectivity.