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    CD (circular dichroism) is a powerful experimental method for determination of  
    the 2nd structures of peptides and proteins in solution. The percentage of alpha
    helix, beta sheet and random coil in a peptide can be quantitatively determined
    according to its CD spectrum.
  • All CD services include sample preparation and peptide concentration determination
  • 4 repeat scans are performed for each sample. The final spectrum is the average of
    the 4 scans
  • All peptide samples should be sent to us as lyophylized powder
  • peptide samples will be discarded after experiment. If you want your peptide be sent
    back to you, please add $25.00 for CD101 and CD102 and $40.00 for CD103.
  • 10% discount will be offered if peptides are ordered from us
  • we provide contract research of using CD to study peptide or protein structure,
    stability, ligand-protein interaction, effect of mutation on the conformation and others.
    Please email us your project. We will send you a free evaluation..
EZBiolab Custom Peptide Service
CD Spectroscopy to Determine Peptide Secondary Structure
    Sample Requirement




    since concentration is critical for quantitative determination of the 2nd structure of a peptide, it is
    very helpful if your peptide has a Tyr or Trp in the sequence. This allows the concentration of
    the peptide to be accurately determined by spectroscopy method. For the peptides that do not
    have an internal Tyr or Trp, we suggest you to add a Tyr at the either end of the peptide. If you
    experiments do not allow to add an extra residue, please to send us at least 5 mg sample to
    minimize the error introduced by weighing.
    Service and Price
    Single point reading (catalog #: CD101)
        CD signal intensity at 222 nm or 215 nm.
        Result reported in molar ellipticity (mean residue ellipticity).
        Price: $125.00 per read for 1-2 samples
                   $100.00 per read for 3-5 samples
                   $85.00 per read for >5 samples
        Peptide amount: 5 mg

     Full spectrum collection (catalog#: CD102)
        CD spectrum from 190 nm to 260 nm
        Price: $150.00 per sample for 1-2 samples
     $125.00 per sample for 3-5 samples
      $110.00 per sample for >5 samples
       Peptide amount: 5 mg

     Five concentration TFE titration (catalog# CD103)
        Full spectra from 190 nm to 260 nm recorded in 0, 20, 40, 60 and 80% TFE
        Price: $285.00 per sample, spectra collection only
                   $385.00 per sample, spectra collection and data analysis
        Sample amount: 10 mg
    Peptide purity
 >95%
    Peptide amount
 experiment depentent (see above)
    Peptide length
 no limitation
For more information
and order our CD
service, please email us
peptide @ezbiolab.com
 
Peptide CD and TFE
Titration  
TFE (triflluoroethenol) is
well know for its ability to
promote alpha helix
formation. Many peptides
that show random coiled
CD spectra in aqueous  
solution become helices
when TFE is added. The
extent of the helical
structure in a given amount
of TFE depends on the
sequence. For two peptides
that both show little helical
structure in aqueous
buffers, one could show
higher helical structure in
TFE. The intrinsic helical
propensity ( or the stability
of helical structure) of a
peptide can be determined
by record a series of CD
spectra as a function of
TFE concentration.