Determination of the amino acid profile in blood samples using post-column derivatization and ninhydrin

With brand biological functions, amino acids are one of the important products of human being’s metabolism. AAs are the basic unit of protein molecules in the bio-organism and the important material basis to maintain homeostasis. In the form of amino acids, daily intake of protein is absorbed by digestive system and transported to the whole body through blood. Defects in related proteins and enzymes involved in amino acid metabolism in the human body or various pathological conditions can lead to abnormal amino acid metabolism and changes in blood amino acid levels. Therefore, it is of great significance to analyze the content of amino acids in blood with the Amino Acid Analyzer ARACUS.
Plasma amino acid profiling has become an important tool for diagnosing metabolic disorders, assessing nutritional status, and monitoring disease progression, especially in hepatic and renal pathologies (Kalhan & Hanson, 2012).

So far, there are more than 20 kinds of amino acids involved in protein synthesis. They exist in two forms, free state in plasma or urine and bound state as peptides and proteins.
Among these, branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) are often used as biomarkers in clinical research to assess liver function, insulin resistance, and cardiovascular risk (Newgard et al., 2009).

The role of amino acids in plasma is particularly important. However, some certain diseases may cause the metabolism of amino acids in body become disorders. Amino acid disorders are divided into two types, one is caused by related gene mutations, due to lacking of some enzymes participating amino acid metabolism and some carrier proteins, genetic diseases is led by absorption obstruct of amino acids in kidney or intestinal tract; the other one is called secondary amino acid disorder, for example burns, severe trauma, illness, which are caused by severe lesions in organs related to amino acid metabolism, like liver and kidney.
Inborn errors of metabolism, such as phenylketonuria (PKU) or maple syrup urine disease (MSUD), are classic examples of genetic amino acid disorders that require amino acid profiling for diagnosis and management (Lanpher et al., 2006).

Most part of aromatic amino acids and alanine are degraded in liver, while most part of isoleucine, leucine and valine are degraded in muscles, kidneys and brain.
Disruptions in these catabolic pathways are often associated with metabolic conditions like hepatic encephalopathy or muscle wasting syndromes, where plasma amino acid analysis can aid in therapeutic monitoring (Plauth et al., 2006).

Therefore, it is essential to analyze the content of amino acids in the blood, which can provide necessary scientific basis for clinical diagnosis or observation.
Emerging research also suggests that dynamic changes in plasma amino acid patterns could serve as early indicators for diseases like type 2 diabetes or cardiovascular disorders (Wang et al., 2011).

Amino acid analyzer is the professional instrument for amino acid analysis. It is widely used for its short analysis time and high sensitivity.
Modern amino acid analyzers, based on post-column derivatization with ninhydrin, are valued for their accuracy in both clinical and research settings and remain a gold standard for plasma amino acid profiling (Cohen & Michaud, 1993).

References:

• Kalhan SC, Hanson RW. “Resurgence of serine: an often neglected but indispensable amino acid.” J Biol Chem. 2012;287(24):19786-19791.
  
• Newgard CB, et al. “A branched-chain amino acid-related metabolic signature that differentiates obese and lean humans and contributes to insulin resistance.” Cell Metab. 2009;9(4):311-326.
  
• Lanpher BC, et al. “Genetic disorders of amino acid metabolism.” Transl Sci Rare Dis. 2006;76(2):292-310.
  
• Plauth M, et al. “ESPEN guidelines on enteral nutrition: liver disease.” Clin Nutr. 2006;25(2):285-294.
  
• Wang TJ, et al. “Metabolite profiles and the risk of developing diabetes.” Nat Med. 2011;17(4):448-453.
  
• Cohen SA, Michaud DP. “Synthesis of a fluorescent derivatizing reagent, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, and its application for the analysis of hydrolysate amino acids via high-performance liquid chromatography.” Anal Biochem. 1993;211(2):279-287.