Welcome to the Biotage Peptide Synthesis Blogs.

      Post synthesis workup: What steps are necessary and what aren't?

      Jun 19, 2019 5:35:32 PM / by Elizabeth Denton posted in Developments, Peptides, workflow, peptide workflow, solid phase peptide synthesis, cleavage

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      You’ve just finished a peptide synthesis and now it’s time to cleave the peptide from the resin. You’ve selected a specific cleavage cocktail, performed the reaction and now what? The vast majority of peptide chemists will precipitate their peptide using an ether solution, lyophilize, and move on to purification. But is that the only option?

      In today’s post I’ll highlight an alternative strategy that saves both processing time, potentially dangerous reagents, all without compromising the integrity of the recently synthesized peptide.

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      Room temperature allyl ester and alloc deprotections - what is the lifetime of palladium?

      Jun 11, 2019 8:30:33 PM / by Elizabeth Denton posted in solid phase peptide synthesis, orthogonal protecting groups, selecting deprotection, synthesis optimization

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      In a previous post, I did some work evaluating the efficiency of alloc removal with tetrakis palladium using microwave assistance and atmospheric conditions, which worked beautifully.  Given the known sensitivity of palladium catalysts (see Derek Lowe's post for a humorous dialogue), I sought to further explore the sensitivity of palladium towards the alloc removal in the context of a peptide.

      In this post, I'll explore a variety of atmospheric, room temperature alloc deprotection conditions aimed at evaluating the catalytic lifetime of palladium tetrakis for effective alloc removal. 

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      How to choose the right resin functionality for solid phase peptide synthesis

      Jun 11, 2019 8:30:01 PM / by Elizabeth Denton posted in Peptides, solid phase peptide synthesis, synthesis tips, synthesis optimization

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      As a chemist new to the peptide community, there are many choices that have to be made.  Which coupling reagents to use? Heat or no heat to promote chemistry? And most importantly, which resin?  I have talked previously about resin choices, from loading levels to swelling capacity and how they affect the synthesis outcome.  But I haven't addressed yet a fundamental feature of commercially available resins, and that's the functional handle to which the peptide chain is conjugated.

      In today's post, I'll describe some, and I mean only some, of the most commonly used chemical functionalities for Fmoc-based solid phase peptide synthesis and some scenarios in which you would choose one resin type over another.

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      Can you use normal phase chromatography to purify protected peptides?

      Jun 11, 2019 8:29:38 PM / by Elizabeth Denton posted in normal phase, reversed-phase, flash purification, peptide synthesis, solid phase peptide synthesis, peptides and flash chromatography

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      Chemical synthesis of peptides, and even proteins, offers the possibility to expand the functionality and stability imbued by nature.  However, chemical synthesis of very long peptides and small proteins remains today an exceedingly difficult task.  Several ligation strategies have been developed that help to alleviate this challenge.  These strategies though, require a purified, yet fully protected peptide fragment.

      Purification of a fully protected peptide species can be challenging by standard reversed-phase techniques, primarily due to the limited solubility of protected peptides in aqueous solutions.  In today’s post, I will discuss using normal-phase chromatography for purification of protected peptides.

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      Using microwave heating to expedite your allyl ester or alloc deprotection

      Jun 11, 2019 8:28:51 PM / by Elizabeth Denton posted in peptide, peptide synthesis, solid phase peptide synthesis, orthogonal protecting groups, synthesis optimization

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      Orthogonal amino acid protecting groups effectively expand the chemical tool kit available to peptide chemists allowing for synthesis of much more complex molecules.  Often times, orthogonal protecting groups are used in Fmoc-based chemistry to facilitate post-synthesis modifications of peptides, like the addition of small molecule fluorophores and more commonly now, peptide cyclization efforts.

      In a previous post, I discussed optimizing the removal of an ivDde protecting group.  In today’s post, I’ll explore the removal of an alloc protecting group from a lysine residue.

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