Classical amino acids

Syntheses of Fluorine-Containing Amino Acids by Methods of Classical Amino Acid Chemistry ... 

The classical amino acids are those that are incorporated into proteins during polymeri2ation in the cell. Table 1.3 lists the 20 classical amino acids in order of one... 

Table 13 The Ti enty Classical Amino Acids Li ed in Order of Their Approximpte Relative Incieafiing Hydrophilicity ...

Although the amino group appears to be "tied up/ it still can participate in the formation of a polypeptide chain. Hydroxyprioline, a modified form of proline, is not one of the 20 classical amino acids but is found in structural proteins such as those of connective tissues. 

As stated earlier, only classical amino acids are built into polypeptides during amino acid polymerization, Howe er, other amino adds, classical amino acids that have been modified after incorporation into the chain, are found in proteins. >ome of the modified amino acids found in proteins are listed in Table 1.4. Vitamins ate required for the synthesis of some of the modified amino acids. For example, vitamin C is required for conversion of proiine to hydroxyproline. This and other vitamin cofactors are listed in Table T4. 

An unusual amino acid behaves like the classical amino acids. The amino acid selenocysteine is incorporated into the polypeptide chain during amino acid polymerizahon. The story of selenwySleine is revealed in the Selenium section in Chapter 10. 

In Table 1.5 the classical amino acids are segregated according to their necessity in the diet, Those that are required to maintain life are called indispensabJe (essenfioJ) amino acids. Those that may be present in the diet but can be omitted without threatening life are called dispensable (norte5sc dw0 amino acids. The proteins of the most value, from a nutritional point of view, are the ones that contain all the indispensable amino acids as well as a variety of dispensable amino acids. 

Studies with rats revealed that it was possible to omit methionine from the diet and replace it with two other chemicals that ace not classical amino acids. Describe this diet after... 

Of all the classical amino acids, with the exception of glycine, only the 2different groups, that is, a carboxyl, hydrogen, amino, and R group. Bonding of four different groups to any carbon atom can occur in two different isomeric arrangements. In amino acids, these are called the L-amino acids and D-amino adds. Essentially, all the amino acids in the diet and in the body occur as the L-isomer. In this textbook, all references to amino adds are to the L-isomer unless otherwise specified. D-Amino acids occur in small quantities in certain... 

Tolman, V. Syntheses of fluorine-containing amino acids by methods of classical amino acid chemistry. Fiuorine-Containing Amino Acids 1995, 1-70. 

HPLC and GLC of derivatised amino acids are overtaking the classical amino acid analyser (the Moore and Stein ion-exchange separation plus post-column ninhy-... 

The method of choice to overcome these problems with the chemical quantification of proteins, peptides, or free amino acids are the classic amino acid analysis methods. 

The complete amino acid sequence of 2050 residues of the mature vWf was established by Titani et al. (270). Most of the sequence analysis was performed by classical amino acid sequencing methods, but some of the gaps and overlaps were established with the use of the DNA sequence information of the long 3 cDNA clone isolated by Sadler et al. (48). 

In addition to the classical amino acid derivative catalysis, a wide group of miscellaneous small organic... 

These peptides are formed from classical amino acids and are cytotoxic and antiproliferative in vitro, with IC50 values ranging from 0.1 to 10[xgml , depending on the peptide and the cell line used. A few of them have been patented. Figures 19.60-19.62 present some of these structures. 

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