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Product Information :

Product Name:  
เครื่องสังเคราะห์เปปไทด์/Peptide Synthesizer


Product Category:   เครื่องมือวิทยาศาสตร์ / สารเคมีและวัสดุภัณฑ์สำหรับห้องปฏิบัติการ
Product Sub-Category:   Life Science
Brand:   CEM Corporation 
Product Type :   สินค้า, ผลิตภัณฑ์ 
Short Description :   Peptide synthesizer CEM DiscoverBio: The world's best selling microwave peptide synthesizer
     
 
DiscoverBio

Manual Microwave Peptide Synthesizer
 
Now the world's best selling microwave peptide synthesizer is also available in a research scale benchtop system that offers a cost-effective alternative to purchasing peptides. Enhance your laboratory's capabilities with the benefits of microwave-assisted peptide synthesis. Now, chemists who need to make peptides on a research scale can produce high purity peptides in a rapid and cost-effective manner.

  • Greater purity peptides than conventional synthesis
  • Accelerated reaction rates - 10 to 20 times faster than conventional methods
  • Access peptides impossible to synthesize under conventional conditions
 
Compared to conventional methods, the Discover Bio offers chemists the unparalleled benefits of microwave-assisted peptide synthesis in a safe, compact, easy-to-use system. The Discover Bio features the same patented technology of the Discover® System, the best-selling microwave synthesis system in the world.
  • Patented single-mode microwave cavity ensures homogenous power delivery at 1W increments
  • Precise fiber optic temperature control
  • Fast, easy washing
  • Small system footprint fits easily in a standard fume hood
  • Easily upgradeable to automated system
  • Accessory available for high pressure organic synthesis
  • Industry-leading safety features

Advantages

Best in Class Technology
  • Integrated washing and reagent delivery system
  • Two reaction vessels cover wide scale range (5 to 1000 µmol)
  • Fiber optic probe for most accurate temperature measurement
  • Inert atmosphere providing cleaner chemistry
  • Nitrogen bubbling for efficient agitation
  • Vessel's integrated spray head allows efficient washing
Benefits
  • Capable of performing full microwave process for deprotection AND coupling
  • Greater purity peptides than conventional synthesis
  • Get your peptides faster than ever with cycle times under 15 minutes
  • Replaceable frit provides low consumable cost
  • Flexible system can be used for both peptide and small molecule organic synthesis
  • Upgradable to fully automated Liberty Blue system
Specifications
 
 
Synthesis Scale 0.025 – 1 mmol
Reaction Vessel Sizes 4 and 25mL polypropylene vessel
Chemistry Fmoc or t-Boc (no HF cleavage)
Temperature Sensor In situ Fiber-Optic
Agitation Inert gas bubbling
Waste Container 1L reservoir standard
Patents US7393920; US7582728; US8058393; EP1491552; JP4773695, with additional worldwide patents pending

Technology

Solid Phase Peptide Synthesis Basics

Solid phase peptide synthesis, originally developed by Bruce Merrifield in 1963, has proven to be a major enabling tool for the creation of peptide sequences. Synthesis of a peptide chain on a solid support offers separation from soluble reagents and simple filtration and washing steps. However, byproducts from incomplete couplings, side reactions, and impurities can build up on the solid support with the desired product. Peptides are composed of amino acids, which are chemically linked together through a peptide bond.

The basic steps for the creation of a peptide on a resin are: 

Deprotection - this process removes the Fmoc group from the N-terminus of the growing peptide chain and permits the next amino acid to be coupled. 

Wash - the resin containing the peptide is washed thoroughly with solvent several times to completely clean the resin before beginning the coupling reaction. 

Coupling - an amino acid is added to the peptide chain. This process requires activation of the amino acid before it can be connected to the growing peptide chain. 

Wash - the resin containing the peptide is washed thoroughly with solvent several times to completely clean the resin before beginning the deprotection reaction of the next cycle. 
Note: 
Steps 1 through 4 are repeated until the desired peptide sequence is assembled on the resin. The last step is to cleave the peptide from the resin and collect it. 

Cleavage - the peptide is cleaved from the resin.


Side Reactions
 
There are any side reactions that may occur during SPPS. Most have been well documented in literature and there mechanisms are known. Listed below are some of the most common side reactions known to occur.

Racemization

Racemization is always a consideration in peptide synthesis. Naturally occurring biologically active amino acids are almost exclusively found in the L-conformation at their α-carbon, however racemization can convert the L-conformation to the D-conformation. Glycine with an R group equal to hydrogen does not have a chiral α-carbon.  
L-conformation D-conformation

Removal and reattachment of the hydrogen atom attached to the α-carbon represents a potential mechanism for enantiomerization. During amino acid activation, the acidity of the α-carbon proton increases. However, this does not appear to be significant mechanism of enantiomerization. Another route to enantiomerization is deprotonation and oxazolone formation.

In general, enantiomerization through oxazolone formation is rarely encountered with stepwise synthesis except for histidine and cysteine. However, special coupling chemistries for these amino acids have largely circumvented the problem. 


Aspartimide Formation
This very common side reaction occurs with aspartic acid or asparagine. The reaction occurs from formation of a five-membered imide. This intermediate can undergo a series of fates that result in various side products as shown below. 
This side reaction occurs most frequently with peptides containing the Asp(OtBu)-X sequence, where X = Asn(Trt), Gly, Ser, Thr. 


Guanidinium Formation
A capping reaction can form when excess uronium activator versus amino acid is added to the reaction vessel, leading to guanidinium formation. Thus, when using HBTU activation, a 0.9/1 ratio of activator/amino acid is recommended


Dehydration
The amino acids asparagine and glutamine have been shown to undergo dehydration at elevated temperatures. This side reaction involves the loss of a water molecule from the side chain groups of these two amino acids. With microwave peptide synthesis, the deprotection and coupling reaction temperatures are elevated and can cause dehydration of the side chains of these two amino acids when they are exposed. For this reason it is necessary to use side chain protecting groups on these two amino acids with microwave peptide synthesis. Both of these amino acids are commonly available with side chain protecting groups. Below are the recommended side chain protecting groups that will prevent dehydration during the peptide chain assembly. These protecting groups will be removed during the final acid cleavage of the peptide; therefore, it is essential that this reaction temperature be minimized. Experts in the CEM peptide synthesis laboratory have designed appropriate cleavage methods that prevent dehydration.

When creating a new cleavage method for a particular peptide, an excessive amount of power delivered to the peptide can increase the bulk temperature of the reaction enough to cause dehydration of a peptide containing asparagine or glutamine. For assistance with cleavage methods, contact the CEM peptide application support group.

Recommended protection of Asparagine and Glutamine:
Fmoc-Asn(Trt)-OH
Fmoc-Gln(Trt)-OH


Diketopiperazine Formation
This side reaction can occur if Glycine or Proline amino acid is at the first or second position on the peptide chain from the resin. This side reaction leads to cleavage from the resin of the first two amino acids in what is called a diketopiperazine.
 

Peptide Purification

Purification of synthetic peptides is an important process for obtaining a final peptide product. This is a well documented process that, when followed, allows a final peptide product of high purity. Traditionally, the following steps are followed for purification. 

Synthetic Peptide Purification

• Evaporate TFA - This step is typically performed with a standard laboratory rotary evaporator for removal of excess TFA from the sample. The peptide is soluble in TFA and the less present that more that will precipitate in the ether addition step. This step is not always performed, but it can lead to higher yield of peptide.

• Precipitation with ether and centrifuge
Ether Precipitation - Ice cold ether added to the peptide dissolved in TFA will lead to precipitation of the peptide from the TFA solution. Typically, diethyl or t-butyl methyl ether are used. Peroxide-free ether should be used for precipitation. For each 1mL of TFA solution, add 10mL of ether for complete precipitation.

Diethyl Ether t-butyl methyl ether (MTBE)

• 
Purity check with Analytical LC/MS

• 
Sample Purification with Preparative LC/MS

• 
Lyophilization


 

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