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Inhibition of rat liver glutathione S-transferase isoenzymes by peptides stabilized against degradation by gamma-glutamyl transpeptidase.
J Biol Chem 1991; 266(2):830-6JB

Abstract

Inhibitors for glutathione S-transferase (GST) iso-enzymes from rat liver with high affinity for the glutathione-binding site (G-site) have been developed. In previous studies, a model was described for the G-site of GST (Adang, A. E. P., Brussee, J., van der Gen, A., and Mulder, G. J. (1990) Biochem. J. 269, 47-54) in terms of essential and nonessential interactions between groups in glutathione (GSH) and the G-site. Based on this model, compounds were designed that have high affinity for the G-site but cannot be conjugated. In the dipeptide gamma-L-glutamyl-D-aminoadipic acid (gamma-L-Glu-D-Aad), the L-cysteinylglycine moiety is replaced by D-aminoadipic acid. This dipeptide is an efficient competitive inhibitor (toward GSH) of mu class GST isoenzymes with Ki values of 34 microM for GST isoenzyme 3-3 and 8 microM for GST isoenzyme 4-4. Other GSH-dependent enzymes, such as gamma-glutamyl transpeptidase (gamma-GT), glutathione reductase, and glutathione peroxidase, were not inhibited by 1 mM of gamma-L-Glu-D-Aad. Inhibition is also highly stereospecific since gamma-L-Glu-L-Aad is only a poor inhibitor (Ki = 430 microM for GST 3-3). Gamma-L-Glutamyl-D-norleucine also had a much higher Ki value for GST 3-3. Thus, the presence of a delta-carboxylate group in D-Aad appears to be essential for a high affinity inhibitor. An additional hydrophobic group did not result in increased inhibitory potency. In a different approach, the gamma-L-glutamyl moiety in GSH was replaced by delta-L-aminoadipic acid; delta-L-Aad-L-Cys-Gly is an efficient cosubstrate analogue for GSTs with Km values comparable to GSH and Vmax values ranging from 0.24 to 57 mumol/min/mg for the different GSTs. The structures of the efficient inhibitor and the cosubstrate analogue were combined in delta-L-Aad-D-Aad, which had a Ki value of 68 microM with GST 3-3. In order to investigate their possible use in vivo studies, the degradation of gamma-L-Glu-D-Aad and delta-L-Aad-L-Cys-Gly by gamma-GT was investigated. The peptides showed no measurable hydrolysis rates under conditions where GSH was rapidly hydrolyzed. Thus, an efficient, mu class-specific GST inhibitor and a gamma-glutamyl-modified cosubstrate analogue of GSH were developed. Their gamma-GT stability offers the possibility to use these peptides in in vivo experiments.

Authors+Show Affiliations

Division of Toxicology, University of Leiden, The Netherlands.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

1670775

Citation

Adang, A E., et al. "Inhibition of Rat Liver Glutathione S-transferase Isoenzymes By Peptides Stabilized Against Degradation By Gamma-glutamyl Transpeptidase." The Journal of Biological Chemistry, vol. 266, no. 2, 1991, pp. 830-6.
Adang AE, Brussee J, van der Gen A, et al. Inhibition of rat liver glutathione S-transferase isoenzymes by peptides stabilized against degradation by gamma-glutamyl transpeptidase. J Biol Chem. 1991;266(2):830-6.
Adang, A. E., Brussee, J., van der Gen, A., & Mulder, G. J. (1991). Inhibition of rat liver glutathione S-transferase isoenzymes by peptides stabilized against degradation by gamma-glutamyl transpeptidase. The Journal of Biological Chemistry, 266(2), pp. 830-6.
Adang AE, et al. Inhibition of Rat Liver Glutathione S-transferase Isoenzymes By Peptides Stabilized Against Degradation By Gamma-glutamyl Transpeptidase. J Biol Chem. 1991 Jan 15;266(2):830-6. PubMed PMID: 1670775.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Inhibition of rat liver glutathione S-transferase isoenzymes by peptides stabilized against degradation by gamma-glutamyl transpeptidase. AU - Adang,A E, AU - Brussee,J, AU - van der Gen,A, AU - Mulder,G J, PY - 1991/1/15/pubmed PY - 1991/1/15/medline PY - 1991/1/15/entrez SP - 830 EP - 6 JF - The Journal of biological chemistry JO - J. Biol. Chem. VL - 266 IS - 2 N2 - Inhibitors for glutathione S-transferase (GST) iso-enzymes from rat liver with high affinity for the glutathione-binding site (G-site) have been developed. In previous studies, a model was described for the G-site of GST (Adang, A. E. P., Brussee, J., van der Gen, A., and Mulder, G. J. (1990) Biochem. J. 269, 47-54) in terms of essential and nonessential interactions between groups in glutathione (GSH) and the G-site. Based on this model, compounds were designed that have high affinity for the G-site but cannot be conjugated. In the dipeptide gamma-L-glutamyl-D-aminoadipic acid (gamma-L-Glu-D-Aad), the L-cysteinylglycine moiety is replaced by D-aminoadipic acid. This dipeptide is an efficient competitive inhibitor (toward GSH) of mu class GST isoenzymes with Ki values of 34 microM for GST isoenzyme 3-3 and 8 microM for GST isoenzyme 4-4. Other GSH-dependent enzymes, such as gamma-glutamyl transpeptidase (gamma-GT), glutathione reductase, and glutathione peroxidase, were not inhibited by 1 mM of gamma-L-Glu-D-Aad. Inhibition is also highly stereospecific since gamma-L-Glu-L-Aad is only a poor inhibitor (Ki = 430 microM for GST 3-3). Gamma-L-Glutamyl-D-norleucine also had a much higher Ki value for GST 3-3. Thus, the presence of a delta-carboxylate group in D-Aad appears to be essential for a high affinity inhibitor. An additional hydrophobic group did not result in increased inhibitory potency. In a different approach, the gamma-L-glutamyl moiety in GSH was replaced by delta-L-aminoadipic acid; delta-L-Aad-L-Cys-Gly is an efficient cosubstrate analogue for GSTs with Km values comparable to GSH and Vmax values ranging from 0.24 to 57 mumol/min/mg for the different GSTs. The structures of the efficient inhibitor and the cosubstrate analogue were combined in delta-L-Aad-D-Aad, which had a Ki value of 68 microM with GST 3-3. In order to investigate their possible use in vivo studies, the degradation of gamma-L-Glu-D-Aad and delta-L-Aad-L-Cys-Gly by gamma-GT was investigated. The peptides showed no measurable hydrolysis rates under conditions where GSH was rapidly hydrolyzed. Thus, an efficient, mu class-specific GST inhibitor and a gamma-glutamyl-modified cosubstrate analogue of GSH were developed. Their gamma-GT stability offers the possibility to use these peptides in in vivo experiments. SN - 0021-9258 UR - https://www.unboundmedicine.com/medline/citation/1670775/Inhibition_of_rat_liver_glutathione_S_transferase_isoenzymes_by_peptides_stabilized_against_degradation_by_gamma_glutamyl_transpeptidase_ L2 - http://www.jbc.org/cgi/pmidlookup?view=long&pmid=1670775 DB - PRIME DP - Unbound Medicine ER -