Peptide polypeptides

A key biochemical reaction of ammo acids is their conversion to peptides polypeptides and proteins In all these substances ammo acids are linked together by amide bonds The amide bond between the ammo group of one ammo acid and the carboxyl of another IS called a peptide bond Alanylglycme is a representative dipeptide... 

Weidner, H., Engel, J., Fietzek, P, Peptides, Polypeptides and Proteins, Part V., John Wiley and Sons, New York 1974... 

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... 

Keywords Biomaterial Drug delivery Hydrogel Peptide Polypeptide Self-assembly Tissue engineering... 

Amidation refers to the replacement of a protein s C-terminal carboxyl group with an amide group (COOH — CONH2). This PTM is usually characteristic of peptides (very short chains of amino acids), as opposed to the longer polypeptides, but one therapeutic polypeptide (salmon calcitonin, Chapter 11) is amidated, and amidation is required for full functional activity. Overall, the function(s) of amidation is not well understood, although in some cases at least it appears to contribute to peptide/polypeptide stability and/or activity. 

The peptide/polypeptide product is usually hydrolysed by incubation with 6 mol l-1 HC1 at elevated temperatures (110 °C), under vacuum, for extended periods (12-24 h). The constituent amino acids are separated from each other by ion-exchange chromatography and identified by comparison with standard amino acid preparations. Reaction with ninhydrin allows subsequent quantification of each amino acid present. 

Figure 7.5 The Edman degradation method, by which the sequence of a peptide/polypeptide may be elucidated. The peptide is incubated with phenylisothiocyanate, which reacts specifically with the N-terminal amino acid of the peptide. Addition of 6 mol l-1 HCl results in liberation of a phenylthiohydantoin-amino acid derivative and a shorter peptide, as shown. The phenylthiohydantoin derivative can then be isolated and its constituent amino acid identified by comparison to phenylthiohydantoin derivatives of standard amino acid solutions. The shorter peptide is then subjected to a second round of treatment, such that its new amino terminus may be identified. This procedure is repeated until the entire amino acid sequence of the peptide has been established...

Since hot add hydrolysis was required to release practically all of the amino adds and amino sugars from the soils, it is likely that the amino adds occur in soils in the form of peptides, polypeptides, and proteins dosely assodated with and protected by SOM and inorganic soil constituents such as clay minerals and hydrous oxides of iron and aluminum. Similarly, amino sugars do not appear to exist in soils as free compounds. 

Hruby, V. J. Al-Obeidi, F. Sanderson, D. G. Smith, D. D., In Innovations and Perspectives in Solid Phase Synthesis Peptides, Polypeptides and Oligonucleotides, Epton, R., Ed. ... 

X axis biogenetic class (A = alkaloids P = amino acids, peptides, peptides, polypeptides and proteins FA/PO = fatty acids and polyketides S = shikimates C = carbohydrates). 

What do a peptide, polypeptide, and protein all have in common ... 

Because they contain two functional groups, amino acids can react to produce condensation polymers by forming amide bonds. These polymers are called peptides, polypeptides, or proteins. Although there is no universally accepted distinction, the term protein is usually reserved for naturally occurring polymers that contain a relatively large number of amino acid units and have molecular masses in the range of a few thousand or larger. The term peptide is used for smaller polymers. 

Krimm S, Bandekar J. Vibrational spectroscopy and conformation of peptides, polypeptides and proteins. Adv Protein Chem 1986 38 181-365. 

Because our research is focused on problems relevant to secondary structure of proteins in solution, this section will briefly review the recent developments in spectroscopic techniques applied to this problem. These techniques are considered low-resolution methods which provide global insight into the overall secondary structure of proteins without being able to establish the precise three-dimensional location of individual structural elements [707], Vibrational spectroscopy has played a pioneering role in studying the conformations of peptides, polypeptides, and proteins [702]. The advent of stable and powerful lasers has led to the development of Fourier transform methods which allows the use of powerful computational techniques for the analysis of spectral data [10,103,104], Laser... 

Waglerin-1 (= 22 amino acid peptide)] (polypeptide) Wagler s pit viper venom GABAA-R chloride current block (3)... 

In detailed studies examining the influence of the volume fraction of the organic modifier, i] , on A Hearn and Grego have shown (/7n-/7c, 30,44, 54a) for a large variety of peptides, polypeptides, and proteins that bimodal dependencies exist between and log A over the full 0 < 1 range for... 

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