Technology
Synthetic Peptides
In-House Versus Outsourcing
Synthetic peptides are procured from either commercial sources or from our in-house facility (PSAU) based on the following criteria and considerations.
Outsourcing Criteria and Considerations:
- Peptides up to 30 amino acids and of average degree of complexity.
- Peptides and their conjugates are ordered from a selected vendor based on actual and competitive quotes from several companies. These quotes are solicited for each peptide request from a group of several vendors that were identified over the years as being able to reliably synthesize high-quality peptides at reasonable costs.
- We review peptide QC documentation from vendor.
- Users decide if they want additional analyses (HPLC and/or MALDI-TOF Mass Spectrometry) to verify peptide identity and purity. We routinely find discrepancies between vendor and in-house QCs.
In-House Criteria and Considerations:
- Long ( 30 – 70 amino acids), or complex peptides.
- Most vendors do not want to synthesize peptides with "difficult" sequences.
- Peptides cancelled by vendors due to repeated synthesis or purification problems. We have successfully synthesized more than 80% of the peptides cancelled by vendors due to these difficulties.
- Justified "emergency" requests of peptides qualified otherwise for outsourcing
Quantites and Quality Selection
- Synthetic peptides are generally available in 4 purity ranges: >95% pure, >85% pure, >75% pure, and as unpurified materials. However, other purity ranges can also be accommodated.
- Peptides can be requested in quantities ranging from 1mg to several grams.
- Each peptide supplied to the requester comes with the vendor's Quality Control report that includes High Performance Liquid Chromatography (HPLC) profile and Matrix-Assisted Laser Desorption Ionization, Time-of-Flight (MALDI-TOF MS), or Electrospray Ionization (ESI MS) spectrum.
- For all peptides from commercial sources, we offer, for a nominal fee, in-house Quality Control (HPLC and MALDI-TOF Mass Spectrometry) analyses to verify their purity and identity. This verification QC was implemented to address problems with the quality of some commercial peptides. Because many researchers are not equipped to verify peptide purity and/or identity, or are unaware of the absence of generally accepted quality standards among peptide vendors, our verification service assures that the material they receive is what they order.
- Our typical QC analyses (HPLC and MALDI Mass Spectrometry) can be supplemented, when required, by N-terminal sequencing, amino acid composition, and quantitation and/or Electrospray Mass Spectrometry.
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