Peptide in nature

Polar organic compounds such as amino acids normally do not polymerize in water because of dipole-dipole interactions. However, polymerization of amino acids to peptides may occur on clay surfaces. For example, Degens and Metheja51 found kaolinite to serve as a catalyst for the polymerization of amino acids to peptides. In natural systems, Cu2+ is not very likely to exist in significant concentrations. However, Fe3+ may be present in the deep-well environment in sufficient amounts to enhance the adsorption of phenol, benzene, and related aromatics. Wastes from resinmanufacturing facilities, food-processing plants, pharmaceutical plants, and other types of chemical plants occasionally contain resin-like materials that may polymerize to form solids at deep-well-injection pressures and temperatures. 

Several other cell types have also been shown to secrete histamine-releasing activity, some of which may be peptide in nature (although more work is necessary for a definitive characterization). For example, human lung macrophages cultured for 24 h have been shown to release a soluble factor (12 and 30 kDa) that stimulates isolated human lung mast cells and human basophils to release histamine [ 145]. The generation and release of this factor developed over time (> 1 h) and was blocked by cycloheximide, indicating that protein... 

A peptide is essentially comprised of L-amino acid residues, and the peptide backbone may be critical to provide physicochemical and functional properties. Diverse functionalities induced by peptides in natural protein hydrolysates are being received with much interest in food industries or alternative-medicinal food sciences. The latest year s researches... 

REPETITIVE AND SELF-ASSEMBLING PROTEINS AND PEPTIDES IN NATURE... 

There have been no reports regarding the detection of sweet peptides in naturally occurring foodstuffs other than thaumatin and monellin. 

Substances interfering with this assay include buffers which are amino acid or peptide in nature, such as Tris and Good s buffers, because they give positive color formation. The Cu ions are also susceptible to reduction. This can be detected in practice by appearance of a red precipitate in the reaction mixture. 

All except Tipranavir are peptidic in nature Calculated using CQSAR program [253]... 

Enzymes are well know poly (peptides) with very high catalytic activity. Several groups are synthesizing modified proteins with "artificial" catalytic activity.23 More recently, catalytic antibodies, which are also poly(peptide) in nature, have been developed.20 in addition, the concept of totally artificial enzymes has been pursued vigorously by several groups this has been reviewed recently.2 Research also continues on immobilized enzyme systems.28... 

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