Abstract
Cystine is a good acceptor of the gamma-glutamyl group of gamma-glutamyl donors in the reaction catalyzed by gamma-glutamyl transpeptidase. The product of the enzymatic reaction and an authentic sample of gamma-glutamylcystine were shown to exhibit identical chromatographic and electrophoretic behaviors; acid hydrolysis gave equimolar amounts of cystine and glutamate. In studies with two gamma-glutamyl donors, apparent Km values in the neighborhood of 0.3 mM were found for L-cystine; these values are not far from the concentrations of L-cystine in mammalian blood plasma. At an amino-acid acceptor concentration of about 0.5 mM, L-cystine is somewhat more active than L-glutamine, and much more active than L-cystein. L-gamma-Glutamyl-L-cystine was found to be a good substrate of gamma-glutamyl cyclotransferase. These observations thus indicate that L-cystine is a very active substrate of the gamma-glutamyl transpeptidase-gamma-glutamyl cyclotransferase pathway. In relation to the hypothesis that the gamma-glutamyl cycle functions in animo-acid transport, it may be significant that glutathione (which is the most abundant intracellular form) is a much better gamma-glutamyl donor than glutathione disulfide, while the predominant extracellular form-cystine-is a much better gamma-glutamyl acceptor substrate than cystein.
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- BLACK S. THE BIOCHEMISTRY OF SULFUR-CONTAINING COMPOUNDS. Annu Rev Biochem. 1963;32:399–418. doi: 10.1146/annurev.bi.32.070163.002151. [DOI] [PubMed] [Google Scholar]
- Brigham M. P., Stein W. H., Moore S. THE CONCENTRATIONS OF CYSTEINE AND CYSTINE IN HUMAN BLOOD PLASMA. J Clin Invest. 1960 Nov;39(11):1633–1638. doi: 10.1172/JCI104186. [DOI] [PMC free article] [PubMed] [Google Scholar]
- COLMAN R. F., BLACK S. ON THE ROLE OF FLAVIN ADENINE DINUCLEOTIDE AND THIOL GROUPS IN THE CATALYTIC MECHANISM OF YEAST GLUTATHIONE REDUCTASE. J Biol Chem. 1965 Apr;240:1796–1803. [PubMed] [Google Scholar]
- CONN E. E., VENNESLAND B. Glutathione reductase of wheat germ. J Biol Chem. 1951 Sep;192(1):17–28. [PubMed] [Google Scholar]
- Crawhall J. C., Segal S. The intracellular ratio of cysteine and cystine in various tissues. Biochem J. 1967 Nov;105(2):891–896. doi: 10.1042/bj1050891. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- MAPSON L. W., GODDARD D. R. The reduction of glutathione by plant tissues. Biochem J. 1951 Oct;49(5):592–601. doi: 10.1042/bj0490592. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Meister A. Glutathione, metabolism and function via the gamma-glutamyl cycle. Life Sci. 1974 Jul 15;15(2):177–190. doi: 10.1016/0024-3205(74)90206-9. [DOI] [PubMed] [Google Scholar]
- Meister A. On the enzymology of amino acid transport. Science. 1973 Apr 6;180(4081):33–39. doi: 10.1126/science.180.4081.33. [DOI] [PubMed] [Google Scholar]
- Nickerson W. J., Romano A. H. Enzymatic Reduction of Cystine by Coenzyme I (DPNH). Science. 1952 Jun 20;115(2999):676–678. doi: 10.1126/science.115.2999.676. [DOI] [PubMed] [Google Scholar]
- Orlowski M., Meister A. The gamma-glutamyl cycle: a possible transport system for amino acids. Proc Natl Acad Sci U S A. 1970 Nov;67(3):1248–1255. doi: 10.1073/pnas.67.3.1248. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Orlowski M., Richman P. G., Meister A. Isolation and properties of gamma-L-glutamylcyclotransferase from human brain. Biochemistry. 1969 Mar;8(3):1048–1055. doi: 10.1021/bi00831a036. [DOI] [PubMed] [Google Scholar]
- RACKER E. Glutathione reductase from bakers' yeast and beef liver. J Biol Chem. 1955 Dec;217(2):855–865. [PubMed] [Google Scholar]
- RACKER E. Glutathione-homocystine transhydrogenase. J Biol Chem. 1955 Dec;217(2):867–874. [PubMed] [Google Scholar]
- RALL T. W., LEHNINGER A. L. Glutathione reductase of animal tissues. J Biol Chem. 1952 Jan;194(1):119–130. [PubMed] [Google Scholar]
- ROMANO A. H., NICKERSON W. J. Cystine reductase of pea seeds and yeasts. J Biol Chem. 1954 May;208(1):409–416. [PubMed] [Google Scholar]
- SEMENZA G. Chromatographic purification of cysteinyl-glycinase. Biochim Biophys Acta. 1957 May;24(2):401–413. doi: 10.1016/0006-3002(57)90212-3. [DOI] [PubMed] [Google Scholar]
- Segal S., Crawhall J. C. Characteristics of cystine and cysteine transport in rat kidney cortex slices. Proc Natl Acad Sci U S A. 1968 Jan;59(1):231–237. doi: 10.1073/pnas.59.1.231. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Segal S., Smith I. Delineation of cystine and cysteine transport systems in rat kidney cortex by developmental patterns. Proc Natl Acad Sci U S A. 1969 Jul;63(3):926–933. doi: 10.1073/pnas.63.3.926. [DOI] [PMC free article] [PubMed] [Google Scholar]
- States B., Segal S. Distribution of glutathione-cystine transhydrogenase activity in subcellular fractions of rat intestinal mucosa. Biochem J. 1969 Jun;113(2):443–444. doi: 10.1042/bj1130443. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tate S. S., Meister A. Interaction of gamma-glutamyl transpeptidase with amino acids, dipeptides, and derivatives and analogs of glutathione. J Biol Chem. 1974 Dec 10;249(23):7593–7602. [PubMed] [Google Scholar]
- Tate S. S., Meister A. Stimulation of the hydrolytic activity and decrease of the transpeptidase activity of gamma-glutamyl transpeptidase by maleate; identity of a rat kidney maleate-stimulated glutaminase and gamma-glutamyl transpeptidase. Proc Natl Acad Sci U S A. 1974 Sep;71(9):3329–3333. doi: 10.1073/pnas.71.9.3329. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tietze F. Disulfide reduction in rat liver. I. Evidence for the presence of nonspecific nucleotide-dependent disulfide reductase and GSH-disulfide transhydrogenase activities in the high-speed supernatant fraction. Arch Biochem Biophys. 1970 May;138(1):177–188. doi: 10.1016/0003-9861(70)90297-3. [DOI] [PubMed] [Google Scholar]
- Tietze F. Disulfide reduction in rat liver. II. Chromatographic separation of nucleotide-dependent disulfide reductase and GSH-disulfide transhydrogenase activities of the high-speed supernatant fraction. Biochim Biophys Acta. 1970 Dec 16;220(3):449–462. doi: 10.1016/0005-2744(70)90276-7. [DOI] [PubMed] [Google Scholar]
- Van der Werf P., Orlowski M., Meister A. Enzymatic conversion of 5-oxo-L-proline (L-pyrrolidone carboxylate) to L-glutamate coupled with cleavage of adenosine triphosphate to adenosine diphosphate, a reaction in the -glutamyl cycle. Proc Natl Acad Sci U S A. 1971 Dec;68(12):2982–2985. doi: 10.1073/pnas.68.12.2982. [DOI] [PMC free article] [PubMed] [Google Scholar]