
Peptides are proteins used to prepare epitome-specific antibodies. In organic chemistry, the synthesis of peptides entails linking amino acids via peptide bonds. The peptide synthesis process involves creating a peptide bond between two amino acids. However, synthesizing proteins can present sequence-based challenges such as aggregation that affect the overall product. You can overcome these challenges is to choosing a peptide synthesizer that can help optimize the synthesis. With a lot of information regarding peptide synthesis, here are the five essential things to know.
Peptide deprotection
The peptide deprotection stage is essential to secure a high-quality product in peptide synthesis. Amino acids have multiple reactive groups during the process, creating further reactions. In most cases, these reactions hurt the peptide synthesis by reducing the chain’s length and causing it to branch. ELISA kits save time and money with highly sensitive and accurate broad range assays in comparison to standard colorimetric immunoassays.
You can minimize side reactions during peptide synthesis by analyzing how an amino acid reactive group can bind to a functional group and prevent nonspecific reactions. Individual amino acids react with the protective groups before being used in peptide synthesis. This process is known as deprotection, which happens shortly after coupling. The process involves amino acids binding correctly to the growing peptide chain.
When selecting the deprotection reagent, you must consider several factors to reduce side reactions and by-product formation. The idea is to ensure all protective groups remain after the peptide synthesis is complete until the nascent peptides are removed.
Amino acid coupling
Coupling refers to forming a peptide bond between two adjacent amino acids. Synthetic peptide coupling requires activating the C-terminal carboxylic acid on the incoming amino acid. The unprotected amino acids react with the unprotected carboxylic acid group to form a peptide bond.
Scientists use carbodiimide activation to achieve synthetic peptide coupling. In most cases, the amino acid coupling uses the dicyclohexycarbodiimide (DCC) or the diisopropyl carbodiimide (DIC) as the coupling reagents. These are common reagents because they react quickly with a carboxyl group to form a highly reactive O-acylisourea intermediate. The reactive nature of carbohydrate amino acids results in several racemizations.
The reactive nature of carbohydrate amino acids means there is a risk of several racemizations occurring. You can reduce their risk of racemizations by adding the O-acylisourea intermediate, which firms a less-reactive intermediary. The coupling reagents act as activators used in forming the peptide bond both in solid-phase and liquid-phase synthesis.
Peptide cleavage
Technological advancements have made it possible to mass-produce peptides in the laboratory. However, several reactions with free protecting groups like incomplete deprotection can result in truncated or deletion sequences or isomers during the process. Adverse effects on the peptide synthesis can occur during the process, with longer peptide sequences having a greater chance of negatively impacting the peptide synthesis.
You can purify peptides by preparative or semi-preparative HPLC. The purification considers factors such as gradient and flow rate, determined by the size of the column and sequence of the peptide. Peptide purification entails using separation strategies to leverage physicochemical properties like size and hydrophobicity.
The reverse phase chromatography (RPC) is the most widely used method in peptide purification. The technique removes all impurities during syntheses, such as isomers and deletion sequences. It eliminates peptides with underground side reactions with free coupling and protecting groups.
Peptide synthesis strategies
Peptide synthesis strategies allow creativity and imagination. They are important in preventing undesirable side reactions during peptide synthesis. In the past, scientists used liquid phase peptide synthesis to synthesize proteins. This is still one of the most common methods used in peptide synthesis. The benefit of using this method is detecting side reactions because of the regular product purification after every step. It also makes it possible to perform convergent synthesis, which involves synthesizing peptides into sequence and linking them to the larger molecules.
However, solid-phase synthesis is the most common method used today in peptide synthesis. Instead of a chemical group protecting the c-terminus, the first amino acid in the solid-phase synthesis has the c-terminus coupled to a rigid activated support. This creates a two-fold method will the resin to function as a C-terminal protective group. It makes it easy to separate the peptide product from the various reaction mixtures during the synthesis process.
Peptide purification
Technology advancements have made it possible to mass-produce peptides in the laboratory. However, during the process, several reactions with free protecting groups like incomplete deprotection can result in truncated or deletion sequences or isomers. Negative effects on the peptide synthesis can occur during the process, with longer peptide sequences having a greater chance of negatively impacting the peptide synthesis.
You can purify peptides by preparative or semi-preparative HPLC. The purification considers factors such as gradient and flow rate, determined by the size of the column and sequence of the peptide. Peptide purification entails using separation strategies to leverage physicochemical properties like size and hydrophobicity.
The reverse phase chromatography (RPC) is the most widely used method in peptide purification. The method removes all impurities during syntheses, such as isomers and deletion sequences. It also eliminates peptides with underground side reactions with free coupling and protecting groups.
Bottom line
Peptide synthesis has been widely used in research studies. It applies in different biological manufacturing processes that allow for the high-throughput production of peptides. You must carefully perform peptide synthesis to avoid side reactions. Previously, this was a complex process that produced low yields. Most laboratories and production facilities synthesize long peptides to maximize reaction efficiency.
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