Role of proteins and peptides

SPANIER AND MILLER Role of Proteins and Peptides in Meat Flavor... 

Spanier, A.M. J.A. Miller The role of proteins and peptides in meat flavor. In Food Flavor and Safety Molecular Analysis and Design, Spanier, A.M., Okai, H., Tamura, M., Eds. ACS Symposium Series No. 528 American Chemical Society Washington, D.C. 1993 pp 78-97. 

The amide functionality plays an important role in the physical and chemical properties of proteins and peptides, especially in their ability to be involved in the photoinduced electron transfer process. Polyamides and proteins are known to take part in the biological electron transport mechanism for oxidation-reduction and photosynthesis processes. Therefore studies of the photochemistry of proteins or peptides are very important. Irradiation (at 254 nm) of the simplest dipeptide, glycylglycine, in aqueous solution affords carbon dioxide, ammonia and acetamide in relatively high yields and quantum yield (0.44)202 (equation 147). The reaction mechanism is thought to involve an electron transfer process. The isolation of intermediates such as IV-hydroxymethylacetamide and 7V-glycylglycyl-methyl acetamide confirmed the electron-transfer initiated free radical processes203 (equation 148). 

LC/MS analysis of proteins and peptides is an important part of drug discovery process, as illustrated in this chapter. The combination of various HPLC techniques and advanced MS methods provides unique analytical capabilities of structural identifications for therapeutic proteins and target proteins. The continuous evolution of proteomics research provides both an opportunity and a challenge for further developments in separation techniques and MS characterization methods. It is expected that these analytical techniques will continue to play important roles in drug discovery in the future. 

In addition to being the building blocks of proteins and peptides, amino acids serve as precursors of many kinds of small molecules that have important and diverse biological roles. Let us briefly survey some of the biomolecules that are derived from amino acids (Figure 24.29). 

The biochemical role of proteolytic enzymes is to catalyse the hydrolysis of proteins and peptides either intra- or extra-cellularly and this is a process that is thermodynamically favoured ... 

The potential for use of this technology remains great. With the continuing refinement of protein purification methods and improved handling and transfer techniques, it seems reasonable to expect that new and important information concerning structure-function relationships of proteins and peptides will be obtained often with very small amounts of material. The central role that amino acid analysis technology will play in these developments seems assured. 

Dialkyl H-phosphonates are used not only for the preparation of N-protected amino acids, but also as active coupling agents in the peptide synthesis [89,115,116], Among a wide variety of methods for the synthesis of peptides, the procedure via mixed carboxylic-phosphoric anhydride-type intermediate has so far attracted attention because this compound plays an important role in the biosynthesis of proteins and peptides [117]. Zhao et al. [89] offer the following reaction scheme for the synthesis of peptides. Phenylalanine and tryptophane are nsed as amino acids. 

Both oligonucleotides [3] and peptides [4] can now be synthesized in an automated fashion, making them widely available. Non-experts can perform the synthesis of oligonucleotides and peptide on a routine basis. That development has allowed much progress in understanding the precise role of proteins and nucleic adds in biological systems. 

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