Histidine arginine and

NL Benoiton, YC Lee, R Steinauer. Determination of enantiomers of histidine, arginine and other amino acids by HPLC of their diastereomeric A-ethoxycarbonyldipep-tides. Pept Res 8, 108, 1995. 

DEAE-cellulose. A paucity of tyrosine residue may reflect the unusual low absorbance of adrenodoxin in the region of 280 mp. In general, the amino acid composition of adrenodoxin is similar to that of spinach ferredoxin as compared in Table 3, but it considerably differs from that of Cl. pasteurianum ferredoxin which lacks amino acid residues of methionine, tryptophan, histidine, arginine, and leucine. 

For instance, Brilliant-Orange is bound to basic amino acids (histidine, arginine and lysine), and it is therefore used for assaying proteins in corn. Amido Black is prefers for determining milk proteins. From the available commercial kits Pierce s microprotein rapid stat kit and Bio-Rad Protein Assay Kit can be shown as examples. Examples of protein analysers based on this principle are also given in Table 11. 

Our ongoing studies aimed to gain an insight Into the biochemical basis of this observed interaction between LDL and pectin have revealed that selective modification of basic amino acid residues such as histidine, arginine and lysine, found in LDL caused a significant loss of interaction between pectin and LDL. These results suggest that various basic amino acids are involved in the observed interaction between pectin and LDL (23). 

The concentration in wort of the amino acids isoleucine, valine, phenylalanine, glycine, alanine, tyrosine, lysine, histidine, arginine and leucine, are considered important [37]. Changes in the concentrations of amino acids in wort will undoubtedly influence nitrogen metabolism because the yeast amino acid is principally derived from the wort amino acid. 

Some ammo acids have side chains that bear acidic or basic groups As Table 27 3 indicates these ammo acids are characterized by three values The third pK reflects the nature of the side chain Acidic ammo acids (aspartic and glutamic acid) have acidic side chains basic ammo acids (lysine arginine and histidine) have basic side chains The isoelectric points of the ammo acids m Table 27 3 are midway between the pK values of the zwitterion and its conjugate acid Take two examples aspartic acid and lysine Aspartic acid has an acidic side chain and a pi of 2 77 Lysine has a basic side chain and a pi of 9 74... 

The 20 common amino acids can be further classified as neutral, acidic, or basic, depending on the structure of their side chains. Fifteen of the twenty have neutral side chains, two (aspartic acid and glutamic acid) have an extra carboxylic acid function in their side chains, and three (lysine, arginine, and histidine) have basic amino groups in their side chains. Note that both cysteine (a thiol) and tyrosine (a phenol), although usually classified as neutral amino acids, nevertheless have weakly acidic side chains that can be deprotonated in strongly basic solution. 

Flgvire 4.5 The influence of endcapping on peak shape and retention of soee PTH-anino acids using a reversed-phase separation system. Peak identification 1 PTH-histidine, 2 PTH-arginine and 3 PTH-valine. (Reproduced with permission from ref. 71. Copyright Preston Publications, Inc.)... 

When the pH of ribonuclease was raised to 8.0 from 5.5 a second site became partially occupied in which the platinum bound to histidine 119. At the lower pH this group would be protonated and blocked. As stated above for this reason groups such as terminal —NH2, arginines and lysines are not likely to be as effective as thio-ether in displacing chloride from chloride complexes of platinum. (We are grateful to Dr. L. Johnson (Oxford) for supplying us with much of this information). 

In dilute aqueous solution, formaldehyde can react with a variety of amino acids. However, the primary initial targets are lysine and cysteine. The primary amine moiety of lysine can accept two methylol adducts. Other amino acids with which formaldehyde reacts include arginine and tyrosine, which are particularly reactive, as well as histidine, serine, tryptophan, glutamine, and asparagine.2 ... 

Many recent studies have focused on the mechanisms of formaldehyde modification, cross-linking, and reversal.19,37 8 In general, these studies found that formaldehyde is very specific, particularly when reaction times are relatively short. The amino-termini, lysine, tryptophan, and cysteine are the targets of modification in this case. Longer reaction times reveal more extensive modifications, including arginine, histidine, tyrosine, and phenylalanine. 

The amine containing side chains in lysine, arginine, and histidine typically are exposed on the surface of proteins and can be derivatized with ease. The most important reactions that can occur with these residues are alkylation and acylation (Figure 1.8). In alkylation, an active... 

ROS can modify amino acid side chains, with histidine, tryptophan, cysteine, proline, arginine, and lysine among those most susceptible to attack (Brown and Kelly 1994). As a result, carbonyl groups are generated, and these carbonyl concentrations can be measured directly in plasma by using atomic absorption spectroscopy, fluorescence spectroscopy, or HPLC following reaction with 2,4-dinitrophenylhydrazine. 

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