Peptides prebiotic systems

In few, if any, of the studies made so far, has an effort been made to correlate the synthesis of peptides with that of oligonucleotides. A plausible prebiotic system capable of producing both oligonucleotides and peptides would be specially significant. In line with this suggestion, recent studies in our laboratory, with the collaboration of D. W. Nooner and E. Stephen-Sherwood, have shown that the same system that we have used earlier for the synthesis of oligothymidylic acid will also condense free amino acids to oligopeptides. 

Various comprehensive studies on the polymerization of enantiopure and racemic esters of a-amino acids performed at the air/water interface to yield peptides have been reported over the years [189,190]. Recent reinvestigations of the products of these reactions by MALDI-TOF MS have demonstrated, however, that they are not longer than dipeptides [191]. For this reason, such esters cannot be regarded as realistic prebiotic model systems for the formation of long oligopeptides. On the other hand, amphiphilic Na-carboxyanhydrides [192] and thio-esters [193] of a-amino acids yield longer oligopeptides. 

Particularly important here is the role of transition metal sulfides. In 1988 Wachtershauser proposed that pyrite, abundant in hydrothermal vent systems, provided an energy source for the first life. He suggested that pyrite provided the catalyst necessary to drive a number of essential chemical reactions which are important precursors to life. More recent studies have confirmed this view and have shown that the sulfides of Fe, Ni, Co, and Zn can play an important role in the fixation of carbon in a prebiotic world (Cody et al., 2004). Transition metal sulfides also play a role in more advance organic synthesis, and Huber and Wachtershauser (1998) showed how amino acids were converted into their peptides using a (NiFe)S catalyst. 

Novel foods include those providing protein (soy and dairy), and those that are intended to improve cardiovascular health (stanol esters, P-glucan, bioactive peptides, and n-3 fatty acids), bone and joint health (calcium, glucosamine, and chondroitin), eye health (lutein), the immune system (milkmicronutrients, lactoferrin, lactoperoxidase, and colostrum), gut health (probiotics and prebiotics), body fitness (conjugated linoleic acid, amino acids, and glyco-macropeptide), energy level, and for beauty. 

Enantioselective enriching processes lead to homochirality [20] in amino acids, which is not a consequence of, but a prerequisite for the origin of life. Mutation and selection formed the first self-replicating, but stUl prebiotic, molecular systems of catalytically highly active peptides and oligoribonucleotides. Ultimately, macroscopic asymmetry derived a posteriori from non-linear amplification mechanisms. [21,22]... 

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