Recent Advances in the Solid- and Solution-Phase Synthesis of Peptides and Proteins Using Microflow Technology

Abstract

Peptides have become increasingly important as drugs and drug candidates. In particular, specialty peptides have garnered considerable attention in recent years because of their improved metabolic stability, higher affinity, and biological target selectivity; some of them have the ability to enable cell membrane permeation and oral administration. Despite its long history, peptide synthesis has various limitations, such as high cost, generation of large amounts of waste, and the requirement for hazardous reagents and solvents. Microflow synthesis, wherein the inner diameter of the reaction tube is ≤1 mm, presents several advantages compared with conventional batch synthesis, such as precise control of the reaction time on a short scale, precise reaction temperature control, and facile scale-up with high reproducibility. Microflow technology has been utilized for peptide synthesis since the beginning of the 21st century. The advantages of microflow synthesis enable the use of highly active and unstable chemical species or high-temperature conditions that accelerate peptide synthesis. The combined use of microflow technology, automated synthesis, and online monitoring technologies has emerged in recent years. This approach not only improved the synthetic efficiency but also afforded large amounts of reliable data that can be used to train machine learning models. This review summarizes the solidand solution-phase syntheses of α-peptides and specialty peptides, including N-methylated peptides, β-peptides, and cyclic peptides, reported mainly after 2017. The recently reported mesoflow peptide syntheses (inner diameter of the reaction channels > 1 mm), the microflow automated syntheses, and in-line analysis are covered in this review.

Rational Design of Antifungal Peptides Based on the γ-Core Motif of a Neosartorya (Aspergillus) fischeri Antifungal Protein to Improve Structural Integrity, Efficacy, and Spectrum

“…, nikkomycin Z, aureobasidin A, and VL-239) because of some unfavorable characteristics, limiting their application as antifungal drugs . These include instability due to host enzyme degradation, poor pharmacodynamic and pharmacokinetic properties compared with conventional drugs, unsolved routes of administration, low yield production, and high production cost. , The recent new solid- and solution-phase peptide synthesis techniques can reduce the production cost and overcome the challenges of antimicrobial peptide production by biological expression systems, such as low yield, degradation, and activity loss . Rational peptide design, chemical modification, and development of drug delivery systems can improve the stability and bioavailability of AFPs …”

A liquid-phase continuous-flow peptide synthesizer for preparing C-terminal free peptides

“…7 Continuous-flow peptide syntheses have been reported over the last two decades. 8 Automation of chemical processes improves scalability, safety, efficiency, and reproducibility 9 and is compatible with continuous-flow synthesis. 9,10 Pentelute et al developed an automated continuous-flow solid-phase peptide synthesizer that produces long peptides in a relatively short time.…”

An identification method to distinguish monomeric sugar isomers on glycopeptides

“…Ideally, procedures for the synthesis of glycosylated amino acids would require only a single step using commercial starting materials and would run as continuous rather than batch processes to provide the needed building block for immediate use in solid-phase peptide synthesis (SPPS) protocols to synthesize the glycopeptide standards. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] Shorter reaction times than the several hours reported to date would also be helpful. 26,27 New automated methods for synthesis using simple parts such as HPLC and syringe pumps and opensource software have the potential to produce building blocks on demand.…”