Amino Acids, Polypeptides, and Proteins

Fischer used Curtius method to separate mixtures of amino acids from protein hydrolyzates by fractionally 

By 1905, Fischer had investigated twenty-nine polypeptides and examined their behavior with various en2ymes. He characterized proteins by the number, nature, and arrangement of the component amino acids. In 1916, Fischer reviewed his work on some one hundred pol3rpeptides and cautioned that these represented only a small fraction of the possible combinations that mi t be found in natural proteins. 

Plants synthesize all the amino acids they require. They do so using as raw material carbohydrates, which they make during photosynthesis, and nitrogen, derived from nitrate ions absorbed from the soil. Animals cannot synthesize all the amino acids required for their regular living, health, and growth. Those they cannot synthesize, known as the essential amino acids, are acquired from plants and/or animals they consume as food. Human beings, for example, acquire nine essential amino acids from their diet. 

In living cells, amino acids are linked into polymeric chains known as polypeptides, typically containing between 10 and 100 amino acids [the 

Alanine Arginine Asparagine Aspartic Acid Cysteine 

Some proteins may be very large, indeed. Titin, for example, a muscle protein and the largest known protein, includes in its molecule over 26,000 combined amino acid units. 

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Sela, M., Synthetic antigens and recent progi ss in immunology, in Peptides. Polypeptides and Proteins. Proceedings of the Rehovot Symposium on Poly (Amino Acids), Polypeptides and Proteins, John Wiley and sons, New York, 1974, pp. 495-509... 

Infrared Analysis of the Structure of Amino Acids, Polypeptides, and Proteins... 

Infrared analysis of the structure of amino acids, polypeptides and proteins. Advanc. Protein. Chem. 7, 291—318 (1952). 

Noguchi, I., and Saito, T. Poly(amino acids), polypeptides and proteins (ed. M. A. Stah-maim),p. 313. Univ. of Wiscon Press 1962. 

Structural Studies of Amino Acids, Polypeptides and Proteins in the SoUd State by CRAMPS NMR... 

We introduce research results from recent proton Combined Rotation and Multiple Pulse Spectroscopy (CRAMPS) NMR of a-amino acids, polypeptides and proteins. Proton CRAMPS NMR research has only just begun and has the possibility of wide-ranging future development. 

E.R. Blout in Poly amino Acids, Polypeptides, and Proteins (M A. Stahmann, ed.). University of Wisconsin Press, Madison, 1962... 

It is astonishing that research to find new drugs was only a small part of Fischer s scientific work. After he went to Berlin his research concentrated mostly on the structure and synthesis of natural products. As already mentioned the first group he worked on was the purines. " Soon afterward he took up research on the constitution and synthesis of carbohydrates and ferments, and this work continued until his death in 1919. Among his most important research was that on amino acids, polypeptides and proteins. Fischers s last notable research subjects were the depsides and tannins. Today people call Fischer one of the first biochemists. He himself remarked in a lecture about organic chemistry ... 

SERS of amino acids, polypeptides and proteins For a successful interpretation of the SERS spectra of proteins it is essential to have detailed information about the SERS behaviour of their monomeric units and simple models. It is reasonable to expect that the intensity of their SERS bands depends on the orientation of the protein molecule with respect to the surface. On the basis of a careful assignment of spectral bands and surface selection rules proposed by Moskovits [63, 80, 81], the orientation of amino acids adsorbed on the surface of colloidal silver was predicted [82-84]. 

Table 5. Amino acids, polypeptides and proteins whose SERS was observed on silver...

Amino acids " are amine derivatives of carboxylic acids and may, in fact, contain a number of amino and carboxylic acid groups. In the simplest case, with one acid and one amino group, the amino group may occupy a or or y, etc., positions. Amino acids, polypeptides and proteins are related compounds... 

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