Amino Acid Analysis

Peptides are often measured and sold in gross weight. The quantitative analysis of peptides is complicated by the presence of water and counterions, which make the net amount of peptide approximately 60-80% of the measured (gross) weight of a peptide. Water and counterions (usually trifluoroacetate, acetate, or chloride) can be measured separately, but net peptide content (NPC) is measured by quantitative amino acid analysis (AAA). Stein and Moore developed AAA as analytical technique for aiding protein structure determination, and their incomparable contribution to biochemistry earned them the Nobel Prize in Chemistry in 1972. Stein and Moore’s technique involves the use of a high-performance cation exchange separation followed by a post-column derivatization that allows sensitive detection of the amino acids. AAA techniques have continued to evolve throughout the years, and at vivitide we have adopted the Waters AccQ•Tag™ System. This system is based on pre-column derivatization of amino acids with a fluorescent tag, followed by reverse phase analysis of the derivatized amino acids on a C18 column. The sensitivity of this technique is in the sub-picomole range.

vivitide is a premier provider of AAA services. This gives additional confirmation of amino acid integrity in the final peptide products, as well as quantitative information about the net peptide content of their product. In this way, customers can order an exact net peptide for their sensitive bioassay work. In addition, catalog products in our online shop ending in -v or -s are vialed by net peptide weight, with the exact peptide content reported on each vial. 

Moreover, the explosion of research in stable isotope dilution (SID)-based mass spectrometry assays for protein quantitation requires AAA to provide exact molar quantitation and/or aliquotting of peptide isotopologues. The NEPTune™ line of peptide products for proteomics applications utilizes AAA to provide accurate and precise AAA measurement of peptide concentrations or amounts for "mass spectrometry assay-ready" custom products.

***Our amino acid analysis assay is tested daily vs NIST protein standards and maintains a coefficient of variation (CV) of <5%.***

Amino Acid Analysis costs $150 per sample for single analysis.

Contact to submit your samples for AAA today.