Peptide synthesis. Part 13. Feedback control in solid phase synthesis. Use of fluorenylmethoxycarbonyl amino acid 3,4-dihydro-4-oxo-1,2,3-benzotriazin-3-yl esters in a fully automated system

Unified schedule for multiple parallel solid-phase synthesis of so-called “difficult” peptides on polypropylene pins was developed. Increase in the efficiency of 9-fluorenyl(methoxycarbonyl) N-terminal amino-protecting group removal was shown to have a greater influence on the accuracy of the “difficult” peptide synthesis than the use of more efficient amino acid coupling reagents such as aminium salts. Hence the unified schedule for multiple parallel solid-phase synthesis of “difficult” peptides included the procedure for N-terminal amino group deprotection modified by applying a more efficient reagent for the deprotection and the standard procedure of amino acid coupling by carbodiimide method with an additional coupling using aminium salts, if necessary. Amino acid coupling with the help of carbodiimide allows to follow the completeness of the coupling via the bromophenol blue indication, thus providing the accuracy of the synthesis and preventing an overexpenditure of expensive reagents. About 100 biotinylated hepatitis C virus envelope protein fragments, most of which represented “difficult” peptides, were successfully obtained by synthesis on pins with the help of the developed unified schedule.

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Synthesis of Asparagusic Acid Modified Lysine and its Application in Solid-Phase Synthesis of Peptides with Enhanced Cellular Uptake

Synlett ◽

10.1055/s-0036-1591847 ◽

2017 ◽

Vol 29 (10) ◽

pp. 1289-1292 ◽

Cited By ~ 5

Author(s):

Pablo Rivera-Fuentes ◽

Alina Tirla ◽

Moritz Hansen

Keyword(s):

Amino Acid ◽

Peptide Synthesis ◽

Cellular Uptake ◽

Building Block ◽

Solid Phase Synthesis ◽

Solid Phase ◽

Solid Phase Peptide Synthesis ◽

Live Cells ◽

Phase Synthesis ◽

Scalable Synthesis

Cyclic disulfides, such as asparagusic acid, enhance the uptake of a variety of cargoes into live cells. Here, we report a robust and scalable synthesis of an asparagusic acid modified lysine. This amino acid can be used in solid-phase peptide synthesis. We confirmed that incorporation of this building block into the sequence of a peptide increases its cellular uptake substantially.

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Efficient Synthesis of Peptides with 4-Methylpiperidine as Fmoc Removal Reagent by Solid Phase Synthesis

Journal of the Mexican Chemical Society ◽

10.29356/jmcs.v58i4.47 ◽

2017 ◽

Vol 58 (4) ◽

Cited By ~ 1

Author(s):

Javier Eduardo García Castañeda ◽

Cristian Francisco Vergel Galeano ◽

Zuly Jenny Rivera Monroy ◽

Javier Eduardo Rosas Pérez

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Peptide Synthesis ◽

Synthetic Peptides ◽

Solid Phase Synthesis ◽

Solid Phase ◽

Solid Phase Peptide Synthesis ◽

Amino Group ◽

Efficient Synthesis ◽

Phase Synthesis

<p>Solid phase peptide synthesis using the Fmoc/<em>t</em>-Bu strategy (SPPS-Fmoc/tBu) is the most widely used methodology for obtaining synthetic peptides. In this paper, we evaluate the viability of using 4-methylpiperidine as a reagent for deprotection of the amino acid alpha amino group in SPPS-Fmoc/tBu. For this purpose, the peptide (RRWQWRMKKLG) was simultaneously synthesized using 4-methylpiperidine or piperidine for Fmoc removal reagent. The obtained products had similar purities and yields. Finally, 21 peptides were synthesized using 4-methylpiperidine. Our results suggest that is possible to obtain synthetic peptides efficiently by the strategy SPPS-Fmoc/tBu when 4-methylpiperidine was used as reagent to remove Fmoc groups N-alpha protected amino acids.</p>

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Oxytocin analogues with non-coded amino acid residues in position 8: [8-Neopentylglycine]oxytocin and [8-cycloleucine]oxytocin

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19872317 ◽

1987 ◽

Vol 52 (9) ◽

pp. 2317-2325 ◽

Cited By ~ 5

Author(s):

Jan Hlaváček ◽

Jan Pospíšek ◽

Jiřina Slaninová ◽

Walter Y. Chan ◽

Victor J. Hruby

Keyword(s):

Amino Acid ◽

Solid Phase Synthesis ◽

Solid Phase ◽

The Other ◽

Amino Acid Residues ◽

Phase Synthesis ◽

Other Hand ◽

Fragment Condensation

[8-Neopentylglycine]oxytocin (II) and [8-cycloleucine]oxytocin (III) were prepared by a combination of solid-phase synthesis and fragment condensation. Both analogues exhibited decreased uterotonic potency in vitro, each being about 15-30% that of oxytocin. Analogue II also displayed similarly decreased uterotonic potency in vivo and galactogogic potency. On the other hand, analogue III exhibited almost the same potency as oxytocin in the uterotonic assay in vivo and in the galactogogic assay.

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Comparison of the Potency of 8-L-Arginine, 8-D-Arginine and 8-D-Homoarginine Vasopressin Analogs with Substituted Phenylalanine in Position 2

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19941439 ◽

1994 ◽

Vol 59 (6) ◽

pp. 1439-1450 ◽

Cited By ~ 2

Author(s):

Miroslava Žertová ◽

Jiřina Slaninová ◽

Zdenko Procházka

Keyword(s):

Amino Acid ◽

Solid Phase Synthesis ◽

Solid Phase ◽

Basic Amino Acid ◽

The Other ◽

Side Chain ◽

Inhibitory Potency ◽

Phase Synthesis ◽

Other Hand ◽

Order Of Magnitude

An analysis of the uterotonic potencies of all analogs having substituted L- or D-tyrosine or -phenylalanine in position 2 and L-arginine, D-arginine or D-homoarginine in position 8 was made. The series of analogs already published was completed by the solid phase synthesis of ten new analogs having L- or D-Phe, L- or D-Phe(2-Et), L- or D-Phe(2,4,6-triMe) or D-Tyr(Me) in position 2 and either L- or D-arginine in position 8. All newly synthesized analogs were found to be uterotonic inhibitors. Deamination increases both the agonistic and antagonistic potency. In the case of phenylalanine analogs the change of configuration from L to D in position 2 enhances the uterotonic inhibition for more than 1 order of magnitude. The L to D change in position 8 enhances the inhibitory potency negligibly. Prolongation of the side chain of the D-basic amino acid in position 8 seems to decrease slightly the inhibitory potency if there is L-substituted amino acid in position 2. On the other hand there is a tendency to the increase of the inhibitory potency if there is D-substituted amino acid in position 2.

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Instrumentation for automated solid phase peptide synthesis

Fmoc Solid Phase Peptide Synthesis ◽

10.1093/oso/9780199637256.003.0017 ◽

1999 ◽

Author(s):

Linda E. Cammish ◽

Steven A. Kates

Keyword(s):

Amino Acid ◽

Peptide Synthesis ◽

Solid Phase ◽

Solid Phase Peptide Synthesis ◽

Reaction Vessel ◽

Automated System ◽

Polymeric Support ◽

Simple Filtration ◽

Subsequent Activation ◽

Selection Of

The concept of solid phase peptide synthesis introduced by Merrifield in 1963 involves elongating a peptide chain on a polymeric support via a two-step repetitive process: removal of the Nα-protecting group and coupling of the next incoming amino acid. A second feature of the solid phase technique is that reagents are added in large excesses which can be removed by simple filtration and washing. Since these operations occur in a single reaction vessel, the entire process is amenable to automation. Essential requirements for a fully automatic synthesizer include a set of solvent and reagent reservoirs, as well as a suitable reaction vessel to contain the solid support and enable mixing with solvents and reagents. Additionally, a system is required for selection of specific solvents and reagents with accurate measurement for delivery to and removal from the reaction vessel, and a programmer to facilitate these automatic operations is necessary. The current commercially available instruments offer a variety of features in terms of their scale (15 mg to 5 kg of resin), chemical compatibility with 9-fluorenylmethyloxycarbonyl/tert-butyl (Fmoc/tBu) and tert-butyloxycarbonyl/ benzyl (Boc/Bzl)-based methods, software (reaction monitoring and feedback control), and flexibility (additional washing and multiple activation strategies). In addition, certain instruments are better suited for the synthesis of more complex peptides such as cyclic, phosphorylated, and glycosylated sequences while others possess the ability to assemble a large number of peptide sequences. The selection of an instrument is dependent on the requirements and demands of an individual laboratory. This chapter will describe the features of the currently available systems. As the field of solid phase synthesis evolved, manufacturers designed systems based on the synergy between chemistry and engineering. A key component to an instrument is the handling of amino acids and their subsequent activation to couple to a polymeric support. The goal of an automated system is to duplicate conditions that provide stability to reactive species that might decompose. Standard protocols for automated synthesis incorporate carbodiimide, phosphonium, and aminium/uronium reagents, preformed active esters, and acid fluorides. For further details on coupling methods, see Chapter 3. A second issue related to coupling chemistry is the time required to dissolve an amino acid and store this solution.

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