Deamidation of proteins

Shih, F.F. 1987. Deamidation of protein in a soy extract by ion-exchange resin catalysis. J Food Sci 52 1529-1531. 

Deamidation of proteins is important for improving functional properties of the product under mild reaction conditions. But enzymatic deamidation of proteins has not had real attention until recently. Kato et al. [155] developed a method for enzymatic deamidation of food proteins by treatment with proteases at pH 10. Salt and disulfide reducing agents have little effect on soy protein deamidation. Heat treatment and proteolysis of soy proteins are the major factors affecting deamidation [156]. 

Artificial protein modification reactions can be induced, for example, deamidation of proteins. 

Deamidation of proteins induces the conversion of glutamine and asparagine residues to acid groups, with the concomitant release of ammonia. Deamidation is known to be an important method for improving the functional properties of proteins, for instance, the increase in solubility of cereal prolamins,... 

Although proteolytic deamidation at alkaline pH was shown to be useful for increasing the surface properties of some proteins, as described earlier, proteolysis is not inevitable for other types of proteins. Furthermore, the alkaline pH condition damaged amino acid residues of protein, for instance, race-mization or the formation of lysinoalanine. Therefore, it is more desirable to use enzymes that catalyze only the deamidation without touching peptide bonds at neutral pH regions. Bacillus circulans peptidoglutaminase was used for the deamidation of proteins. The enzyme was shown to have a very limited... 

Chazin, W. J. and Kossiakoff, A. A. The role of secondary and tertiary structures in intramolecular deamidation of proteins. In Deamidation and Isoaspartate Formation in Peptides and Proteins, (D. W. Aswad, ed.), CRC Press, Washington, DC, pp. 193-206, 1995. 

Deamidation of soy and other seed meal proteins by hydrolysis of the amide bond, and minimization of the hydrolysis of peptide bonds, improves functional properties of these products. For example, treatment of soy protein with dilute (0.05 A/) HCl, with or without a cation-exchange resin (Dowex 50) as a catalyst (133), with anions such as bicarbonate, phosphate, or chloride at pH 8.0 (134), or with peptide glutaminase at pH 7.0 (135), improved solubiHty, whipabiHty, water binding, and emulsifying properties. 

S. J. Wearne and T. E. Creighton, Effect of protein conformation on rate of deamidation Ribonuclease A, Proteins Struct. Funct. Genet, 5, 8 (1989). 

The influence of secondary structure on reactions of deamidation has been confirmed in a number of studies. Thus, deamidation was inversely proportional to the extent of a-helicity in model peptides [120], Similarly, a-hel-ices and /3-turns were found to stabilize asparagine residues against deamidation, whereas the effect of /3-sheets was unclear [114], The tertiary structure of proteins is also a major determinant of chemical stability, in particular against deamidation [121], on the basis of several factors such as the stabilization of elements of secondary structure and restrictions to local flexibility, as also discussed for the reactivity of aspartic acid residues (Sect. 6.3.3). Furthermore, deamidation is markedly decreased in regions of low polarity in the interior of proteins because the formation of cyclic imides (Fig. 6.29, Pathway e) is favored by deprotonation of the nucleophilic backbone N-atom, which is markedly reduced in solvents of low polarity [100][112],... 

An example of this effect is provided by ribonuclease A (RNase A). At pH 8 and 37°, the rate of deamidation of Asn67 was more than 30-fold lower in the native than in the unfolded protein [111]. Deamidation of the native RNase A was also ca. 30-fold slower than of an octapeptide whose sequence is similar to that of the deamidation site, although the reaction mechanisms were similar [108][123],... 

R. Bischoff, H. V. J. Kolbe, Deamidation of Asparagine and Glutamine Residues in Proteins and Peptides Structural Determinants and Analytical Methodology , J. Chro-matogr., B 1994, 662, 261-278. 

A. B. Robinson, C. J. Rudd, Deamidation of Glutaminyl and Asparaginyl Residues in Peptides and Proteins , Curr. Topics Cell. Regul. 1974, 8, 247-295. 

H. T. Wright, Nonenzymatic Deamidation of Asparaginyl and Glutaminyl Residues in Proteins , Crit. Rev. Biochem. Mol. Biol. 1991, 26, 1-52. 

S. Capasso, A. Di Donato, L. Esposito, F. Sica, G. Sorrentino, L. Vitagliano, A. Zagari, L. Mazzarella, Deamidation in Proteins The Crystal Structure of Bovine Pancreatic Ribonuclease with an Isoaspartyl Residue at Position 67 , J. Mol. Biol. 1996, 257, 492 -496. 

K. Patel, R. T. Borchardt, Deamidation of Asparaginyl Residues in Proteins A Potential Pathway for Chemical Degradation of Proteins in Lyophihzed Dosage Form , J. Parent. Sci. Technol. 1990,44, 300-301. 

Robinson N.E. and Robinson A.B. (2001), Prediction of protein deamidation rates from primary and three-dimensional structure, Proc. Nat. Acad. Sci. U.S.A. 98, 4367 1372. 

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