Amino acid analysis
APAF has been providing expert, high quality amino acid analysis (AAA) for industry and researchers for over 20 years. We provide a comprehensive service, using eight different methodologies that cover the huge variety of amino acids and samples types.
Amino acid analysis as a technique was first developed in the 1950s by Stein and Moore and co-workers and in 1972 they received the Nobel prize in chemistry for their contribution to the understanding of protein structure. Since then the technique has been refined and improved in speed and sensitivity by the use of automation and high performance chromatography.
AAA can be used to determine the quantities of individual amino acids, the amino acid ratio or composition and it is regarded as the gold standard for protein and peptide quantification. Colorimetric dye-binding assays are often used to determine protein concentration but these assays are not accurate and vary from protein to protein.
AAA is now applied extensively to provide nutrition data, in quality control, for protein quantitation and in research applications. The main products routinely analysed are:
- Foods for human consumption, particularly, dairy products (such as casein and whey), meats and grains
- Animal feedstuffs for the poultry and pig industries but also for other intensive animal productions such as aquaculture
- Plant material and grains including cereals (such as wheat, rice, sorghum and maize) and pulses such as soybean
- Wine, beer, fruit juice and energy drinks
- Raw materials, such as synthetic amino acids, and waste products
- Protein and peptide based pharmaceuticals
- Synthetic peptides
- Growth media for cell culture
- Collagen and products
- Physiological and metabolite samples (plasma, body fluids, tissue extracts).
Amino acid analysis services:
Amino acids are found either free or more commonly chemically-bound in a protein or peptide. Samples can be analysed for free amino acids or total amino acids (free + protein/peptide bound).
Amino acids are released from proteins and peptides by cleaving the amide bond under carefully controlled conditions using acid hydrolysis. Some amino acids, such as cysteine and tryptophan, are not stable to acid hydrolysis and require an alternative methodology. Once released the amino acids are derivatised then separated, detected and quantified by UPLC (ultra-performance liquid chromatography). AccQ.Tag (Waters Corporation) is employed as the pre-column derivatisation reagent for tagging amino groups.
Summary of amino acids analysed by each assay
|Amino acid profile/high sensitivity AAA||Optional extra amino acids for AA profile/high sensitivity AAA||Free / plasma amino acid profile||Optional extra amino acids for free plasma AA profile||Aminothiols||Specific assays are required for|
|histidine||hydroxyproline||histidine||hydroxyproline||free cysteine||total Cys|
|serine||taurine||asparagine||taurine||free cystine||total tryptophan|
|arginine||ornithine||serine||ornithine||N-acetyl cysteine (NAC)||total glutamine|
|glycine||cysteic acid||arginine||citrulline||homocysteine||total asparagine|
|aspartic acid /asparagine||hydroxylysine||glutamine||1 and 3-methylhistidine||glutathione|
|glutamic acid /glutamine||lanthionine||glycine||GABA||cysteinylglycine (CysGly)|
|threonine||aspartic acid||a-aminoadipic acid (AADA)|
|alanine||glutamic acid||a-aminobutyric acid (AABA)|