Peptide salt-induced

Penetration enhancers are low molecular weight compounds that can increase the absorption of poorly absorbed hydrophilic drugs such as peptides and proteins from the nasal, buccal, oral, rectal, and vaginal routes of administration [186], Chelators, bile salts, surfactants, and fatty acids are some examples of penetration enhancers that have been widely tested [186], The precise mechanisms by which these enhancers increase drug penetration are largely unknown. Bile salts, for instance, have been shown to increase the transport of lipophilic cholesterol [187] as well as the pore size of the epithelium [188], indicating enhancement in both transcellular and paracellular transport. Bile salts are known to break down mucus [189], form micelles [190], extract membrane proteins [191], and chelate ions [192], While breakdown of mucus, formation of micelles, and lipid extraction may have contributed predominantly to the bile salt-induced enhancement of transcellular transport, chelation of ions possibly accounts for their effect on the paracellular pathway. In addition to their lack of specificity in enhancing mem-... 

Fig. 5.6 The formation of alanine and glycine in the salt-induced peptide synthesis reaction (Suwannachot and Rode, 1998)...

Still with the prebiotic scenario, the conditions developed by Limtrakul et al. (1985) are interesting as a consequence of evaporation, high local concentrations may have arisen, and under such conditions the incompletely hydrated metal ions may activate a dehydration leading to peptide condensation. From this, the technique of the salt induced peptide condensation (SIPC) has been developed (Oie et al, 1983 Suwannachst and Rode, 1999 Rode et al, 1999). 

Rode, B. M., Son, H. L. and Suwannachot, Y. (1999). The combination of salt induced peptide formation reaction and clay catalysis a way to higher peptides under primitive earth conditions. Orig. Life. Evol. Biosph., 29, 273-86. 

Salt induced peptide formation [108] is based on a dehydrating activity of concentrated NaCl solutions in which free water molecules are less available, which drives the equilibrium towards peptide formation. This change in the thermodynamic barrier is coupled to a decrease of the kinetic barrier owing to the addition of a Cu(II) salt catalyst. A complex of copper with two amino acid ligands 14 has been proposed to be responsible for the catalytic process. In this way, the reaction between two amino acid ligands leading to peptide bond formation can take place intramolecularly ... 

Importantly, salt-induced peptide formation could provide an abiotic route for the formation of peptides directly from amino acids in concentrated NaCl solutions containing copper ions. Montmorillonite and similar minerals apparently promote the condensation reaction that could have taken place in evaporating tidal pools -Darwin s warm little ponds - where the required salty brine solutions were easily available. Obviously, this is a likely and hence a credible prebiotic scenario. There might a pearl hidden beneath muddy waters. Besides, it is fascinating to assume that the primitive enolase enzyme known to be a highly conserved ancient enzyme could have evolved in an RNA-peptide world. Enolase catalyzes the for enantio-selective carbon-carbon bond addition of water to phosphoenol pyruvate to yield D-2-phospho-glycerate. 

L.A. Carpino, A. El-Faham, Effect of Tertiary Bases on 0-Benzotriazolyluronium Salt-Induced Peptide Segment Coupling, J. Org. Chem. 59 695- 698, 1994. 

HPLC-ICP-MS with nano HPLC-ESI MS/MS allowed the precise quantification and identification of sulfur-containing peptides in tryptic digests of human serum albumin and salt-induced yeast protein (SIP 18) at the picomole level. ... 

It is believed that nickel penetrates the skin and acts as a hapten, complexing with selected peptide and/or amino-acid ligands to distort intercellular or cellular proteins, stimulating a type IV delayed (cell-mediated) hypersensitivity reaction [398]. Nickel water-soluble salts, like nickel chloride and nickel sulphate, are strong sensitizers [213, 215], The chloride induced in sweat is apparently an important factor in dissolving the metallic nickel, permitting the soluble nickel salts to act. 

Sucrose octasulfate (23, Structures 6) bound to FGF and was able to induce, like heparin, a conformational change in the peptide, but showed very low mitogenic activity for an F32 cell line. The basic aluminium salt of sucrose octasulfate, which is used as a drug (Sucralfate, Carafate) for the treatment of duodenal ulcers was claimed to exert part of its activity through the stabilization of FGF... 

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