4 things to remember about Amino Acid Analysis of proteins & peptides

Amino Acid analysis
Alphalyse
Sep 23. 2016

Why perform Amino Acid Analysis?

 
Amino acid analysis is a method to determine the absolute amounts of individual amino acids in a sample. The method can be applied to samples containing free amino acids. However it may also be used on peptides and protein samples after hydrolysis into amino acids [1, 2].
 
Amino acid analysis can be used for determination of the relative composition of amino acids in a protein. It can also be used for determination of the absolute amount of a protein or peptide if the amino acid sequence is known. Finally, it is used for purity estimation of a purified protein [3].
 

In amino acid analysis it should be noted that:

  1. Serine and threonine are degraded slightly during acid hydrolysis, and recoveries can be 10% lower than expected.
  2. Methionine can be oxidized during hydrolysis, usually less than 10% is oxidized.
  3. Valine and isoleucine bonds (Val-Val, Ile-Val, Val-Ile, Ile-Ile) are difficult to hydrolyse and recoveries can be 5-15% lower than expected.
  4. Glycine content is often higher than expected because it is a frequent contaminant due to its use in many buffers. Analysis of known amounts of amino acids standards is used to determine a compensation factor to correct for differences in ninhydrin reactivity [1-3].

 
Read more about Quantitative Amino Acid Analysis >>>
 
 

References:

[1]          Rutherfurd et al: “Amino acid analysis“, Current Protocols in Protein Science, 2009

[2]          Rutherfurd et al: “Quantitative amino acid analysis“, Current Protocols in Protein Science, 2011

[3]          Noble et al: “Quantification of protein“, Methods in Enzymology, 2009

About Alphalyse

Alphalyse uses expertise in the field of protein chemistry and bioinformatics, combined with top-of-the-line mass spectrometry equipment, to provide protein analysis services globally.

Alphalyse aims to deliver high quality data and customer service to all of our clients in a fast and convenient way.

www.alphalyse.com

Newsletter Subscribe to The Alphalyse Newsletter and get more
information on protein analysis methods and applications
© 2019 Alphalyse, Inc.