Abstract
The first efforts to modify the terminal α-amino groups of proteins without reaction of the ɛ-amino groups of lysine residues made use of their lower pK values. A pH below 7 favors modification of weaker bases, since the stronger bases, although more reactive, are protected to an even greater extent by protonation. Unfortunately, this approach only favors modification of terminal over side-chain amino groups to a limited extent. N-Terminal serine and threonine residues may be selectively acylated on the amino group by an acyl transfer reaction after a peptide has been selectively acylated on its hydroxyl groups. This approach is severely limited by the need for the peptide to be stable to the acidic and anhydrous conditions necessary for selective O-acylation, and to the alkaline conditions necessary for removing the remaining O-acyl groups. Terminal serine and threonine residues may also be selectively oxidized by periodate, since this reaction is a thousand-fold faster than other oxidations of periodate, e.g., of 1,2-diols or disulfides. Further, it forms glyoxyloyl groups, which may be converted into terminal glycine residues by transamination. The last observation provided the basis for the one general modification of N-terminal residues, namely their conversion into 2-oxoacyl groups by reaction of the α-amino group with glyoxylate, a reaction catalysed by a bivalent cation, e.g., Cu2+, and a base, e.g., acetate. Participation of the neighboring peptide bond in the reaction ensures specificity of the reaction for the N-terminus. Scission of the N-terminal residue is possible after such a transamination; hence residues may be removed from the N-terminus under nondenaturing conditions. Other exploitations of transamination may be developed.
Similar content being viewed by others
References
Borch, R. F., Bernstein, M. D., and Durst, H. D. (1971).J. Am. Chem. Soc. 93, 2897–2904.
Brown, L. R., De Marco, A., Richarz, R., Wagner, G., and Wüthrich, K. (1978).Eur. J. Biochem. 88, 87–95.
Cabacungan, J. C., Ahmed, A. I., and Feeney, R. E. (1982).Anal. Biochem. 124, 272–278.
Cennamo, C., Carafoli, B., and Bonetti, E. P. (1956).J. Am. Chem. Soc. 78, 3523–3527.
Degani, Y., and Patchornik, A. (1967). InAbstracts 7th International Congress Biochemistry, Tokyo, p. 11.
Dixon, H. B. F. (1964a).Biochem. J. 90, 2C-3C.
Dixon, H. B. F. (1964b).Biochem. J. 92, 661–666.
Dixon, H. B. F. (1968).Biochem. J. 107, 124–126.
Dixon, H. B. F. (1972).Biochem. J. 130, 317.
Dixon, H. B. F., and Fields, R. (1972).Meth. Enzymol. 25, 409–419.
Dixon, H. B. F., and Moret, V. (1964).Biochem. J. 93, 25C-26C.
Dixon, H. B. F., and Moret, V. (1965).Biochem. J. 94, 463–469.
Dixon, H. B. F., and Weitkamp, L. R. (1962).Biochem. J. 84, 462–468.
Edwards, J. O. (1956).J. Am. Chem. Soc. 78, 1819–1820.
Fields, R., and Dixon, H. B. F. (1968).Biochem. J. 108, 883–887.
Geoghegan, K. F., Cabacungan, J. C., Dixon, H. B. F., and Feeney, R. E. (1981).Int. J. Protein Res. 17, 345–352.
Holley, R. W., and Holley, A. D. (1952).J. Am. Chem. Soc. 74, 5445–5448.
Jencks, W. P. (1969). InCatalysis in Chemistry and Enzymology, McGraw-Hill, New York, pp. 79–85.
Means, G. E., and Feeney, R. E. (1968).Biochemistry 7, 2192–2201.
Mix, H., and Wilcke, F. W. (1960).Hoppe-Seyler's Z. Physiol. Chem. 318, 148–158.
Odani, S., and Ikenaka, T. (1978).J. Biochem. 84, 1–9.
Patchornik, A., and Sokolovsky, M. (1964).J. Am. Chem. Soc. 86, 1206–1212.
Reid, E. (1951).Nature 168, 955.
Sarkar, B., Dixon, H. B. F., and Webster, D. (1978).Biochem. J. 173, 895–897.
Waller, J.-P., and Dixon, H. B. F. (1960).Biochem. J. 75, 320–328.
Webster, D., and Offord, R. E. (1972).Biochem. J. 130, 315–317.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Dixon, H.B.F. N-terminal modification of proteins—a review. J Protein Chem 3, 99–108 (1984). https://doi.org/10.1007/BF01024840
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF01024840