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Intracellular glutathione cycling by gamma-glutamyl transpeptidase in tumorigenic and nontumorigenic cultured rat liver cells.
J Biol Chem 1986; 261(11):4986-92JB

Abstract

The nontumorigenic ARL-15C1 and tumorigenic gamma-glutamyl transpeptidase-containing ARL-16T2 cell lines were found to contain approximately equal amounts of glutathione, cysteine, and cystine, 65.6, 3.5, and 5 nmol/mg of protein for ARL-16C1, and 61.5, 3, and 3 nmol/mg of protein for ARL-16T2, respectively. The half-life for glutathione in these cell lines was 3.2 and 3.8 h in the ARL-15C1 and 16T2, respectively. In ARL-15C1 cells, the cysteine half-life was 0.2 h and that of cystine 2.0 h compared to 2.0 h and 0.5 h, respectively, in the ARL-16T2. The turnover of glutathione in the ARL-15C1 could be accounted for by efflux into the medium whereas only 10% of the glutathione expected from ARL-16T2 cells appeared in the medium. The ARL-16T2 cells appear to support glutathione synthesis by conservation and recycling of cysteine residues. Inhibition of gamma-glutamyl transpeptidase by AT-125 (acivicin) caused extensive loss of intracellular glutathione from ARL-16T2 cells but produced no effect on GSH levels in ARL-15C1 cells. No metabolism of medium glutathione by gamma-glutamyl transpeptidase was detected, independent of AT-125 treatment. AT-125 treatment caused a transient increase in intracellular GSH in the ARL-16T2 but not the ARL-15C1, further suggesting that the enzyme catalyzes intracellular GSH recycling to supply cysteine for cellular functions in the tumorigenic ARL-16T2 cell line. Transport of cysteine, cystine, and methionine was not altered by AT-125 treatment. These data are consistent with an intracellular orientation of gamma-glutamyl transpeptidase in this cell line and not participation in extracellular processes.

Authors

No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

2870063

Citation

Meredith, M J., and G M. Williams. "Intracellular Glutathione Cycling By Gamma-glutamyl Transpeptidase in Tumorigenic and Nontumorigenic Cultured Rat Liver Cells." The Journal of Biological Chemistry, vol. 261, no. 11, 1986, pp. 4986-92.
Meredith MJ, Williams GM. Intracellular glutathione cycling by gamma-glutamyl transpeptidase in tumorigenic and nontumorigenic cultured rat liver cells. J Biol Chem. 1986;261(11):4986-92.
Meredith, M. J., & Williams, G. M. (1986). Intracellular glutathione cycling by gamma-glutamyl transpeptidase in tumorigenic and nontumorigenic cultured rat liver cells. The Journal of Biological Chemistry, 261(11), pp. 4986-92.
Meredith MJ, Williams GM. Intracellular Glutathione Cycling By Gamma-glutamyl Transpeptidase in Tumorigenic and Nontumorigenic Cultured Rat Liver Cells. J Biol Chem. 1986 Apr 15;261(11):4986-92. PubMed PMID: 2870063.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intracellular glutathione cycling by gamma-glutamyl transpeptidase in tumorigenic and nontumorigenic cultured rat liver cells. AU - Meredith,M J, AU - Williams,G M, PY - 1986/4/15/pubmed PY - 1986/4/15/medline PY - 1986/4/15/entrez SP - 4986 EP - 92 JF - The Journal of biological chemistry JO - J. Biol. Chem. VL - 261 IS - 11 N2 - The nontumorigenic ARL-15C1 and tumorigenic gamma-glutamyl transpeptidase-containing ARL-16T2 cell lines were found to contain approximately equal amounts of glutathione, cysteine, and cystine, 65.6, 3.5, and 5 nmol/mg of protein for ARL-16C1, and 61.5, 3, and 3 nmol/mg of protein for ARL-16T2, respectively. The half-life for glutathione in these cell lines was 3.2 and 3.8 h in the ARL-15C1 and 16T2, respectively. In ARL-15C1 cells, the cysteine half-life was 0.2 h and that of cystine 2.0 h compared to 2.0 h and 0.5 h, respectively, in the ARL-16T2. The turnover of glutathione in the ARL-15C1 could be accounted for by efflux into the medium whereas only 10% of the glutathione expected from ARL-16T2 cells appeared in the medium. The ARL-16T2 cells appear to support glutathione synthesis by conservation and recycling of cysteine residues. Inhibition of gamma-glutamyl transpeptidase by AT-125 (acivicin) caused extensive loss of intracellular glutathione from ARL-16T2 cells but produced no effect on GSH levels in ARL-15C1 cells. No metabolism of medium glutathione by gamma-glutamyl transpeptidase was detected, independent of AT-125 treatment. AT-125 treatment caused a transient increase in intracellular GSH in the ARL-16T2 but not the ARL-15C1, further suggesting that the enzyme catalyzes intracellular GSH recycling to supply cysteine for cellular functions in the tumorigenic ARL-16T2 cell line. Transport of cysteine, cystine, and methionine was not altered by AT-125 treatment. These data are consistent with an intracellular orientation of gamma-glutamyl transpeptidase in this cell line and not participation in extracellular processes. SN - 0021-9258 UR - https://www.unboundmedicine.com/medline/citation/2870063/Intracellular_glutathione_cycling_by_gamma_glutamyl_transpeptidase_in_tumorigenic_and_nontumorigenic_cultured_rat_liver_cells_ L2 - http://www.jbc.org/cgi/pmidlookup?view=long&pmid=2870063 DB - PRIME DP - Unbound Medicine ER -