1000
C. Lherbet et al. / Bioorg. Med. Chem. Lett. 13 (2003) 997–1000
modelling studies have provided no reason to believe
the heteroatomic analogues adopt any unusual con-
formation that may improve their affinity or reactivity as
acceptor substrates, for example, through the formation
of an intramolecular a-amino to g-hydrogen bond. Per-
haps their improved efficiency is due to their capacity to
be bound in an orientation similar to that of a
(g-)dipeptide, thereby resembling the efficient dipeptide
substrate glycylglycine.
2. Graber, R.; Losa, G. A. Int. J. Cancer 1995, 62, 443.
3. Del Bello, B.; Paolicchi, A.; Comporti, M.; Pompella, A.;
Maellaro, E. FASEB J. 1999, 13, 99.
4. Tate, S. S.; Meister, A. Methods Enzymol. 1985, 113, 400.
5. Castonguay, R.; Lherbet, C.; Keillor, J. W. Bioorg. Med.
Chem. 2002, 10, 4185.
6. Menard, A.; Castonguay, R.; Lherbet, C.; Rivard, C.;
Roupioz, Y.; Keillor, J. W. Biochemistry 2001, 40, 12678.
7. Taniguchi, N.; Ikeda, Y. Adv. Enzymol. Relat. Areas Mol.
Biol. 1998, 239.
8. Calcagni, A.; Dupre, S.; Lucente, G.; Luisi, G.; Pinnen, F.;
Rossi, D. Int. J. Peptide Protein Res. 1995, 46, 434.
9. Calcagni, A.; Dupre, S.; Lucente, G.; Luisi, G.; Pinnen, F.;
Rossi, D.; Spirito, A. Arch. Pharm. Pharm. Med. Chem. 1996,
329, 498.
10. Burg, D.; Filippov, D. V.; Hermanns, R.; van der Marel,
G. A.; van Boom, J. H.; Mulder, G. J. Bioorg. Med. Chem.
2002, 10, 195.
It also appears that the methyl ester group has an adverse
effect on acceptor substrate efficiency, as shown in the
comparison of L-GPNA and 4. A similar comparison
between l-serine (kcat/KM=0.138ꢂ106 minꢀ1 Mꢀ1 23
)
and its methyl ester (Table 1) confirms this pattern. The
corresponding comparison of compounds 8 and 10 was
impossible, since the low solubility of compound 10 at
pH 8.0 made it impractical to determine its efficiency
precisely.
11. Lindsay, H.; Whitaker, J. F. OPPI Briefs 1975, 89.
12. De Macedo, P.; Marrano, C.; Keillor, J. W. Bioorg. Med.
Chem. 2002, 10, 355.
13. Waki, M.; Kitajima, Y.; Izumiya, N. Synthesis 1981, 266.
14. (4): Yellow solid; [a]D +13.3ꢁ (c 1, MeOH); 1H N MR
(D2O, 400 MHz) d 2.22 (m, 2H), 2.62 (m, 2H), 3.72 (s, 3H),
4.14 (t, 1H), 7.59 (d, J=9.1 Hz, 2H), 7.70 (d, J=9.2 Hz, 2H);
13C NMR (CD3OD, 75 MHz) d 26.5, 33.0, 53.4, 54.6, 120.3,
125.8, 144.5, 146.0, 170.6, 172.6; m/z 281.1096 (MH+,
C12H15N3O5 requires 281.1012).
In summary, a new class of compounds containing
heteroatoms at the g-position of the side chain of a glu-
tamyl moiety has been synthesized successfully.
Although compounds 8, 10, and 13 contained a good
leaving group compared to previous heteroatomic glu-
tathione analogues,8ꢀ10 their urethane and carbamate
bonds were found to be resistant to cleavage by purified
rat kidney GGT. The decreased electrophilicity of the
carbonyl group in these compounds and the poor
nucleophilicity of the active site (threonine) nucleophile
of GGT could explain this lack of reactivity. Never-
theless, this class of compounds should prove useful for
enzymes containing a stronger active site nucleophile, as
is the case, for example, for transglutaminase24 and the
cysteine proteases.
15. (8): Yellow solid; [a]D ꢀ26.1ꢁ (c 1, MeOH); 1H N MR
(D2O, 300 MHz) d 3.79 (t, J=4.3 Hz, 2H), 3.84 (s, 3H), 4.30 (t,
1H), 7.52 (d, J=9.2 Hz, 2H), 8.20 (d, J=9.2 Hz, 2H); 13C
NMR (D2O, 75 MHz) d 39.7, 53.7, 54.1, 118.5, 125.5, 142.1,
145.6, 157.0, 169.3; m/z 282.0969 (MH+, C11H14N4O5 requires
282.0964).
16. (10): Yellow solid; [a]D ꢀ27.7ꢁ (c 0.6, MeOH); H N MR
1
(CD3OD, 300 MHz) d 3.58 (br d, J=14.1 Hz, 1H) 3.76 (br d,
J=14.3 Hz, 1H), 4.19 (t, 1H), 7.65 (d, J=8.8 Hz, 2H), 8.12 (d,
J=8.7 Hz, 2H); 13C NMR (CD3OD, 75 MHz) d 40.9, 54.0,
118.7, 125.8, 143.1, 147.3, 157.6, 169.9; m/z 283.1.
17. (13): Yellow solid; [a]D ꢀ16.0ꢁ (c 1, MeOH); 1H N MR
(D2O, 400 MHz) d 3.88 (s, 3H), 4.58 (t, 1H), 4.66 (dd, J=12.5
Hz, J=3.6 Hz, 1H), 4.74 (dd, J=12.4 Hz, J=4.4 Hz, 1H),
7.52 (d, J=9.1 Hz, 2H), 8.18 (d, J=9.1 Hz, 2H); 13C N MR
(D2O, 75 MHz) d 52.7, 54.3, 62.8, 118.9, 125.5, 143.2, 144.3,
153.8, 168.3; m/z MH+ 283.9.
Acknowledgements
This work was supported by the Natural Sciences and
Engineering Research Council (NSERC) of Canada.
The authors also acknowledge the financial support of
the Universite de Montreal for a Bourse d’excellence
Scholarship (C.L.) and NSERC for a Postgraduate
Scholarship (R.C.).
18. Thompson, G. A.; Meister, A. Biochem. Biophys. Res.
Commun. 1976, 71, 32.
19. Menard, A.; Keillor, J. W. MSc Thesis, Universite de
Montreal, 1999.
20. Dvorakova, L.; Krusek, J.; Stastny, F.; Lisy, V. Gen.
Phys. Biophys. 1996, 15, 403.
21. Hegarty, A. F.; Frost, L. N. J. Chem. Soc., Perkin Trans. 2
1973, 1719.
22. Shin, H.-Y.; Quinn, D. M. Biochemistry 1992, 31, 811.
23. Thompson, G. A.; Meister, A. J. Biol. Chem. 1977, 252,
6792.
References and Notes
1. Sian, J.; Dexter, D. T.; Lees, A. J.; Daniel, S.; Jenner, P.;
Marsden, C. D. Ann. Neurol. 1994, 36, 356.
24. Lapierre, D.; Keillor, J. W. Unpublished observations.