Amino acids peptides and polypeptides

The Building Blocks of Proteins Amino Acids, Peptides, and Polypeptides 49 The Three-Dimensional Structures of Proteins 72... 

In the first three chapters of part 2 we discuss the basic structural and chemical properties of proteins. In this chapter we concentrate on the structural and chemical properties of amino acids, peptides, and polypeptides—the building blocks of proteins. From our presentation you will learn the following ... 

Part 2, Protein Structure and Function, contains four chapters that relate to the structures and functions of proteins. In chapter 3, The Building Blocks of Proteins Amino Acids, Peptides, and Polypeptides, we discuss basic structural and chemical properties of amino acids, peptides and polypeptides. In chapter 4, The Three-Dimensional Structures of Proteins, we describe how and why polypeptide chains fold into long fibrous molecules in some cases, or into compact globular molecules in other cases. In chapter... 

Correlations between 2H quadrupole interaction parameters and hydrogen bond geometry have also been considered for situations other than 0-H---0 hydrogen bonds. For example, solid state 2H NMR spectra of 2H labelled amino acids, peptides and polypeptides were measured over a wide temperature range [74]. From spectral simulations based on dynamic 2H NMR theory, parameters such as the 2H quadrupolar coupling constant and asymmetry parameter were determined, and relationships between these NMR parameters and the hydrogen... 

The preparation of polymers containing pendant or terminal amino acids, peptides, and polypeptides has in the past been limited to organic polymers, and so has neglected inorganic polymers such as siloxanes. A novel series of amino acid functional siloxanes, suitable for use in personal care products, have been prepared and characterized for the first time. Such products can be synthesized by a three-step procedure. The preparation of amino acid siloxanes has now been achieved by hydrosilylation of an unsaturated functional amino acid with three hydrido functional siloxanes tetramethyldisiloxane, containing terminal Si-H groups, poly(methylhydrogen)siloxane (DP = 33) and... 

Aguilar, M. I., Hodder, A. N., and Hearn, M. T. W., High-performance liquid chromatography of amino acids, peptides, and proteins. LXV. Studies on the optimisation of the reversed-phase gradient elution of polypeptides. Evaluation of retention relationships with (3-endorphin-related polypeptides, /. Chromatogr., 327, 115, 1985. 

In this section, the structure, function, and reactivity of amino acids, peptides, and proteins will be discussed with the goal of providing a foundation for successful derivatization. The interplay of amino acid functionality and the three-dimensional folding of polypeptide chains will be seen as forming the basis for protein activity. Understanding how the attachment of foreign molecules can affect this tenuous relationship, and thus alter protein function, ultimately will create a rational approach to protein chemistry and modification. 

Amino acids, peptides, and proteins Ninhydrin Very sensitive stain for amino acids, either free or combined in polypeptides used after paper electrophoresis... 

Crystals of several amino-acids and of a few simple peptides and other compounds related to proteins have been analyzed recently by three-dimensional methods. These and other accurate determinations of structure constitute the best experimental sources of information about the dimensions and configuration of the polypeptide chain. The present paper comprises a critical summary of this information— in particular, of the principal structural features of the amide group and the N—H---0 hydrogen bonds, as derived from X-ray diffraction analyses of crystals of amino-acids, peptides, and other organic compounds. 

Peptide is the name assigned to short polymers of amino acids. Peptides are classified by the number of amino acid units in the chain. Each unit is called an amino acid residue, the word residue denoting what is left after the release of HgO when an amino acid forms a peptide link upon joining the peptide chain. Dipeptides have two amino acid residues, tripeptides have three, tetrapeptides four, and so on. After about 12 residues, this terminology becomes cumbersome, so peptide chains of more than 12 and less than about 20 amino acid residues are usually referred to as oligopeptides, and, when the chain exceeds several dozen amino acids in length, the term polypeptide is used. The distinctions in this terminology are not precise. 

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