Peptide chain length

As a result of the en2ymatic degradation of proteins, key indexes change, ie, protein solubiUty indexes (PSI), peptide chain length (PCL), and protein solubihty in 0.8 Af TCA (TCA-index) (Fig. 14). Unpleasant bitterness was once a problem for some protein hydroly2ates. This problem can now be overcome by proper selection of the reaction parameters and the en2ymes used. 

Fig. 14. Time dependence of key indexes during en2ymatic hydrolysis (a) degree of hydrolysis (DH) (b) peptide chain length (PCL) (soluble peptides) (c)...

Chun, H., Sasaki, M., Fujiyama, Y., and Bamba, T. (1996). Effect of peptide chain length on absorption and intact transport of hydrolyzed soybean peptide in rat intestinal everted sac. J. Clin. Biochem. Nutr. 21, 131-140. 

Adler-Nissen and Olsen (40) studied the influence of peptide chain length on the taste anT functional properties of enzymatically modified soy protein. The emulsifying capacity of modified proteins could be improved significantly compared to unmodified control samples by controlling the extent of hydrolysis. 

Depending on the nature of the protein and the protease used, progressive proteolysis can liberate bitter peptides from proteins, the bitterness of which is a function of amino acid composition and sequence as well as the peptide chain length (Adler-Nissen, 1986b). An excellent review of the chemistry of bitterness has been published (Roy, 1997) and the reader is directed to this for more details. 

Adler-Nissen, J. and Olsen, H.S. 1979. The influence of peptide chain length on taste and functional properties of enzymatically modified soy protein In Functionality and Protein Structure , Advances in Chemical Series 92 (A. Pour-El ed.), pp. 125-146. American Chemical Society, Washington, DC. 

The Influence of Peptide Chain Length on Taste and Functional Properties of Enzymatically Modified Soy Protein... 

D. Effect of Peptide Chain Length and Composition on Retention... 

Studies with larger peptides, e.g., polypeptide hormones, have indicated that the resolving power of reversed-phase separations may decrease as the peptide chain length increases. These results stress the importance of using elution conditions which generate adequate relative... 

Free radical species that are capable of initiating vinyl polymerization reactions have been identified as Cu -co-ordinated amino-acid radicals, and these are produced in the primary photoreactions of the complex. An examination of the quantum yield and photodecomposition stoicheiometry of Cu (H2Aib)3 (H2Ajb= a-aminoisobutyric acid) as a function of irradiation wavelength and medium conditions has shown that 7r-copper -amidyl radicals are the primary photoproducts. The behaviour of other Cu -peptide complexes suggests that these photochemical parameters are dependent on the peptide chain-length and the number of a-carbon methyl substituents. ... 

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