title: Methods, setup and safe handling for anhydrous hydrogen fluoride cleavage in Boc solid-phase peptide synthesis.
abstract: Solid-phase peptide synthesis (SPPS) using tert-butyloxycarbonyl (Boc)/benzyl (Bzl) chemistry is an indispensable technique in many laboratories around the globe, and it provides peptides to the pharmaceutical industry and to thousands of scientists working in basic research. The Boc/Bzl strategy has several advantages, including reliability in the synthesis of long and difficult polypeptides, alternative orthogonality regarding protecting groups and ease of producing C-terminal thioesters for native chemical ligation applications. In this process, anhydrous hydrogen fluoride (HF) is used to remove the side chain protecting groups of the assembled peptide and to release the peptide from the resin, a process typically described as 'HF cleavage'. This protocol describes the general methodology, apparatus setup and safe handling of HF, with the aim of providing comprehensive information on the safe use of this valuable, well-studied and validated cleavage technique. We explain the cleavage mechanism, the physicochemical properties and risks of HF, first aid measures and the correct use of the apparatus. In addition, we provide advice on scavenger selection, as well as a troubleshooting section and video material illustrating key steps of the procedure. The protocol comprises precleavage sample preparation (30 min-2.5 h), complete HF cleavage procedure (2 h) and reaction workup (30 min).
authors.affiliation: 1] Institute for Research in Biomedicine Barcelona, Barcelona, Spain. [2] Department of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia.
authors.forename: Markus
authors.initials: M
authors.lastname: Muttenthaler
authors.affiliation: 1] Institute for Research in Biomedicine Barcelona, Barcelona, Spain. [2] The Biomedical Research Networking center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona Science Park, Barcelona, Spain. [3] Department of Organic Chemistry, University of Barcelona, Barcelona, Spain. [4] School of Chemistry, Yachay Tech, Yachay City of Knowledge, Urcuqui, Ecuador.
authors.forename: Fernando
authors.initials: F
authors.lastname: Albericio
authors.affiliation: The Scripps Research Institute, Department of Chemistry, La Jolla, California, USA.
authors.forename: Philip E
authors.initials: PE
authors.lastname: Dawson
mesh_terms: D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry / Q000633:toxicity; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D017751:Safety Management; D060327:Solid-Phase Synthesis Techniques / Q000295:instrumentation / Q000379:methods*
chemical_list: D010455:Peptides; D006858:Hydrofluoric Acid