Amino acid compositional data electrophoresis

After device construction, structural and functional analysis are critical. One might argue that only the second issue matters, but structural data often give insights into why devices perform suboptimally, and provide important clues about how to improve device function. We routinely use protein analytics (matrix-assisted laser desorption-ionization mass spectroscopy, amino acid composition analysis, gel electrophoresis, Western blotting, circular dichroism, vari-... 

The brain enzyme has been purified over 1000-fold and shown to be homogeneous by ultracentrifugation and electrophoresis criteria (36) the activity ratio for acetyl-P over carbamyl-P remains unchanged with purification. This enzyme is one of the smallest on record the molecular weight from physical data is 13,200 and from amino acid analysis is 12,600 the amino acid composition of the enzyme is given in Table I. The terminal amino acid is aspartic acid (25). Cystine has not been detected. 

Amino acid analysis is often touted as the most accurate method for determination of protein concentration. The data from this 1996 ABRF AAA study indicate that the vast majority of member facilities that participated in this study quantitate soluble protein well. The most striking aspect of this study, however, was the ability of the laboratories to identify the protein solely on its amino acid composition. The data from approximately 90% of the participants were sufficient for correct identification, if one knew the species of the protein s origin. Currently, identification of unknown proteins from AAA data is not frequently used for simple soluble proteins, such as triosephosphate isomerase. The technique is more commonly used to identify proteins that have been separated by two dimensional analysis on isoelectric focusing and SDS electrophoresis and then transferred to PVDF membranes. Such samples are usually present in low... 

Purified human BChE (from human serum, -90% pure, as demonstrated by gel electrophoresis, data not shown) and recombinant human AChE-S were from Sigma (Jerusalem, Israel). Enzymatic activity was determined by hydrolysis rates of butyryl- or acetyl-thiocholine, respectively, at 25°C or 4°C, as indicated. Enzyme concentrations were calculated based on the molecular weight of a protein monomer and its known amino acid composition. 

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