Analysis of Amino Acids, determination of the Amino Acids sequence forming a peptide / protein is important as first information about a structure of a complex molecule. Several amino acids are influencing the final structure by cross bindings between amino acids.

Modern analytical methods are established and implemented, at the same time existing and sometimes simple methods are still in and have not lost their place.

 
 
 

Applications for Amino Acid Analysis

 

MALDI-in source decay for the detection of methionine oxidation using the MALDI-8020 benchtop linear MALDI-TOF mass spectrometer

Matrix-assisted laser desorption/ionization is a rapid, simple and sensitive tool for obtaining information on the molecular weight as well as the primary structure of a peptide or protein. Among the different fragmentation methods, in source decay (ISD) is used in ‘top-down’ proteomics to obtain the sequence of proteins. It leads to c- and z-fragment ion series via a hydrogen radical-transfer mechanism. One advantage is ISD over post-source decay (PSD) is that ISD is theoretically not limited by the sample mass and thus allow the sequencing of large proteins directly, without the need of an enzymatic digestion. In the pharmaceutical industry, as part of the quality control (QC) process, it is important to track any changes, either due to product formulation or degradation, as they can affect the therapeutic role, leading to a potential loss of activity or development of toxicity. 

 
 
 
 
 
 

 

N-terminal Amino Acid Sequencing if IgG Antibodies

Recently, the term ‘biomedicine’ is often heard in the field of pharmaceuticals. While also called biopharmaceuticals, they refer to proteinaceous drugs and antibody drugs developed and manufactured using biotechnologies including genetic recombination, cell fusion and cell culture. In contrast, conventional medicines are referred to as ‘low molecular drugs’ and produced through chemical synthesis. While both types are chemical compounds, compared to chemical synthesized low molecular drugs, biomedicines characteristically have much higher molecular weight. In order to guarantee the quality of biomedicines, influences originating from the raw material and manufacturing processes need to be taken into consideration in addition to performing qualification testing of products. 

 
 
 
 
 
 

 

N-terminal Amino Acid Sequencing of Mouse IgG Using the PPSQ-51A/53A Gradient System

As genome analysis technology has evolved, the genome database has become more comprehensive, and proteome analysis which is one form of post-genome analysis using the database - has grown by leaps and bounds. As a result of technical developments in mass spectrometers, we were able to achieve high-throughput analysis in the amino acid sequencing of proteins by using a mass spectrometer and its database. Although many proteins in the genome database are registered as precursor proteins, the various proteins expressed in cells are transported into the body as mature proteins that result from processing of these precursor proteins.

 
 
 
 
 
 

 

Simultaneous Analysis of Chiral Amino Acids - Produced by Intestinal Microbiota using LC/MS/MS

Some of the metabolites produced by intestinal microbiota are constantly absorbed from the intestinal lumen and transported throughout the entire body. In recent years, it has become clear that the intestinal microbiota contributes to the preservation and promotion of the hosts’ health and attention has been focused on the relationship of the intestinal microbiota and metabolites with health and diseases. For this reason, it is extremely important to analyze the metabolites produced by the intestinal microbiota. Amino acids have optical isomers (the D-isomer and L-isomer) and it has long been considered that only L-isomers are involved in the biological world. In this study, we comprehensively analyzed chiral amino acids in mouse colonic contents and blood plasma, using LC-MS/MS, and investigated D-amino acids produced by the intestinal microbiota.

 
 
 
 
 
 

 

Amino Acid Sequence Analysis of Peptides and Proteins with Modified Amino Acid Using PPSQ Isocratic System

Protein identification with a mass spectrometer (MS) and search engine utilizing genomic databases has now become the main stream in analysis of proteins. Although the proteins in the genomic databases are registered as precursor proteins, the expressed proteins in living cells are modified after translation and have various functions. However, since there are differences in the theoretical mass number of the precursor protein and the mature protein modified after translation, the score and reliability of search results obtained by the MS analysis and search engine is sometimes low. Moreover, identification of amino acid sequences by MS without using databases is both quite complex and difficult. On the other hand, a protein sequencer using the conventional Edman degradation method obtains highly reliable sequencing results, and amino acid sequences can be identified easily even in case the database is inadequate. 

 
 
 
 
 
 

 

Analysis of Amino Acids by KBr Tablet Method

In the transmission method, light is irradiated on a measurement sample, and the light that passes through the sample is detected. However, the adequate technique (accessory device) differs depending on the sample shape. Among techniques used with the transmission method, the KBr tablet method is mainly used to measure solids and powders. The KBr tablet method is a necessary and indispensable procedure which has been standardized not only in the Japanese Pharmacopoeia (JP), but also in the United States Pharmacopeia (USP), standards of the American Society for Testing and Materials (ASTM). Special care is necessary in order to obtain a satisfactory spectrum by the KBr tablet method, including securing a uniform powder size and maintaining a constant pressure during tablet forming (pelletizing). In particular, the effect of moisture requires special attention. In this experiment, we conducted an analysis of amino acids, which easily absorb moisture, by the KBr tablet method. 

 
 
 
 
 
 
 

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