Heavy metals peptides

In general, nonconventional protein foods must be competitive with conventional plant and animal protein sources on the bases of cost delivered to the consumer, nutritional value to humans or animals, functional value in foods, sensory quality, and social and cultural acceptability. Also, requirements of regulatory agencies in different countries for freedom from toxins or toxic residues in single-cell protein products, toxic glycosides in leaf protein products, pathogenic microorganisms, heavy metals and toxins in fish protein concentrates, or inhibitory or toxic peptide components in synthetic peptides must be met before new nonconventional food or feed protein products can be marketed. 

Grill, E., Winnacker, E.-L. Zenk, M.H. (1985). Phytochelatins The principal heavy-metal complexing peptides of higher plants. Science, 230, 674-6. 

Hormone response elements (for steroids, T3, retinoic acid, peptides, etc) act as—or in conjunction with— enhancers or silencers (Chapter 43). Other processes that enhance or silence gene expression—such as the response to heat shock, heavy metals (Cd and Zn +), and some toxic chemicals (eg, dioxin)—are mediated through specific regulatory elements. Tissue-specific expression of genes (eg, the albumin gene in liver, the hemoglobin gene in reticulocytes) is also mediated by specific DNA sequences. 

This zinc-dependent enzyme [EC 3.4.11.1], also referred to as cytosol aminopeptidase, leucyl aminopeptidase, and peptidase S, catalyzes the hydrolysis of a terminal peptide bond such that there is a release of an N-terminal amino acid, Xaa-Xbb-, in which Xaa is preferably a leucyl residue, but may be other aminoacyl residues including prolyl (although not arginyl or lysyl). Xbb may be prolyl. In addition, amino acid amides and methyl esters are also readily hydrolyzed, but the rates with arylamides are exceedingly slow. The enzyme is activated by heavy metal ions. 

Steffens, J.C. (1990). The heavy metal-binding peptides of plants. Annual Review of Plant Physiology 41, 553-75. 

E. Chow, Peptide-Modified Electrochemical Sensors for the Detection of Heavy Metal Ions, Vol, The University of New South Wales, Sydney, 2006. 

This is a method by which heavy metal atoms, such as tungsten, may be introduced into peptides and in this way free amino groups can be labeled. 

Coordination complexes in which the metal is coordinated by a bio-ligand present in a biological matrix (e.g., metal-binding peptides which are enzymatically synthesized in living organisms exposed to heavy metal stress). 

Razmiafshari M, Zawia NH (2000) Utilization of a synthetic peptide as a tool to study the interaction of heavy metals with the zinc finger domain of proteins critical for gene expression in the developing brain. Toxicol Appl Pharmacol 166 1-12 Rivest S (2003) Molecular insights on the cerebral innate immune system. Brain Behav Immun 17 13-19... 

The main inspiration for the formation of nanoparticles from single amino acids arose from the fact that in nature, many particles are formed from short chain peptides that contain a cysteine or histidine amino acid. These short chain peptides are principally used as a form of detoxification from the effects of high heavy metal ion concentrations in vivo. From these biological examples, the chemistry of these peptides has been expanded to form novel zero-valent and semiconductor nanoparticles under in vitro conditions (Figure 2). 

Similar metal-binding motifs are common in varions proteins and peptides with metal-binding capabiUties. Snznki etal. examined the metal-binding characteristics of one such protein, the heavy metal-binding protein Cdll9 from Arabidopsis The anthors prepared the 225 amino acid... 

Peptides and proteins could be efficient metal binding ligands, because they have the functional groups for metal binding in their amino acid residues, and they can be produced at low cost by recombinant technologies. While many peptides and proteins are known to work as metal transport proteins in biological systems, metallothioneins (cysteine rich proteins with molecular weight of ca. 7 kDa) have attracted researchers attention for decades because they bind heavy metals in vivo [2]. The metallothioneins are considered to be involved in detoxication and metabolism of heavy metals. 

As an alternative to ammonium iodide/TFA, the use of titanium(IV) chloride/sodium iodide in TFA has been proposed for clevage of the acid-labile protecting groups and reduction of Met(O) residues.However, this reagent, besides bearing all the disadvantages of the use of heavy metals in peptides, leads to time-dependent reduction of disulfide bridges as well as to side products at the level of Trp residues. 

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