Isoelectric Focusing of Glutathione S-Transferases From Rat Liver and Kidney

Hales, Barbara F.; Jaeger, Valerie; Neims, Allen H.

doi:10.1016/b978-0-08-023768-8.51006-9

Cited by 4 publications

(4 citation statements)

References 14 publications

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“…In order to verify whether other class alpha isoforms bind acyl‐CoAs, the isoenzymes of rat liver GST were separated by isoelectric focusing. Four peaks of GST activity of different isoelectric points (P 1 ‐P 4 ) corresponding to the main isoforms present in rat liver [13–15] were thus obtained, as already reported by other authors [32,33]. The electrophoretic pattern of the four fractions together with that of affinity purified GST are shown in Fig.…”

Section: Resultssupporting

confidence: 76%

High‐affinity binding of fatty acyl‐CoAs and peroxisome proliferator‐CoA esters to glutathione S‐transferases

Silva

Loyola

Valenzuela

et al. 1999

European Journal of Biochemistry

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Acyl-CoAs are present at high concentrations within the cell, yet are strongly buffered by specific binding proteins in order to maintain a low intracellular unbound acyl-CoA concentration, compatible with their metabolic role, their importance in cell signaling, and as protection from their detergent properties. This intracellular regulation may be disrupted by nonmetabolizables acyl-CoA esters of xenobiotics, such as peroxisome proliferators, which are formed at relatively high concentration within the liver cell. The low molecular mass acyl-CoA binding protein (ACBP) and fatty acyl-CoA binding protein (FABP) have been proposed as the buffering system for fatty acyl-CoAs. Whether these proteins also bind xenobiotic-CoA is not known. Here we have identified new liver cytosolic fatty acyl-CoA and xenobiotic-CoA binding sites as glutathione S-transferase (GST), using fluorescent polarization and a acyl-etheno-CoA derivative of the peroxisome proliferator nafenopin as ligand. Rat liver GST and human liver recombinant GSTA1-1, GSTP1-1 and GSTM1-1 were used. Only class alpha rat liver GST and human GSTA1-1 bind xenobiotic-CoAs and fatty acyl-CoAs, with K d values ranging from 200 nm to 5 mm. One mol of acyl-CoA is bound per mol of dimeric enzyme, and no metabolization or hydrolysis was observed. Binding results in strong inhibition of rat liver GST and human recombinant GSTA1-1 (IC 50 at the nanomolar level for palmitoyl-CoA) but not GSTP1-1 and GSTM1-1. Acyl-CoAs do not interact with the GSTA1-1 substrate binding site, but probably with a different domain. Results suggest that under increased acyl-CoA concentration, as occurs after exposure to peroxisome proliferators, acyl-CoA binding to the abundant class alpha GSTs may result in strong inhibition of xenobiotic detoxification. Analysis of the binding properties of GSTs and other acyl-CoA binding proteins suggest that under increased acyl-CoA concentration GSTs would be responsible for xenobiotic-CoA binding whereas ACBP would preferentially bind fatty acyl-CoAs.

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Section: Resultssupporting

confidence: 76%

High‐affinity binding of fatty acyl‐CoAs and peroxisome proliferator‐CoA esters to glutathione S‐transferases

Silva

Loyola

Valenzuela

et al. 1999

European Journal of Biochemistry

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“…Although the kidney contains the highest amount of enzyme activity involved in glutathione synthesis and degradation (Meister 1974), expressed per gram of wet tissue, the GST activity is considerably less than in the liver 270 (Hales et al 1978). In the rat (and rabbit), GST localization within the nephron is confined to the early and late proximal convoluted tubule and the proximal straight tubule (Fine et al 1975(Fine et al , 1978Fleischner et al 1976).…”

Section: Introductionmentioning

confidence: 96%

Determination of urinary glutathione S-transferase and lactate dehydrogenase for differentiation between proximal and distal nephron damage

et al. 1990

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Cytosolic glutathione S-transferase (GST) activity is confined to the proximal convoluted and straight tubules. Damage to these parts of the nephron should result in leakage of GST into the urinary space. Lactate dehydrogenase (LDH), in contrast, is more generally distributed along the nephron. Measurement of both enzyme activities could therefore be expected to discriminate between different localizations of nephrotoxicity. To test this hypothesis, we determined both enzyme activities in 24 h urine samples from 10-12 female Sprague-Dawley rats, each treated with single i.p. injections of puromycin aminonucleoside (PAN, 130 mg/kg), Na2 CrO4 10, 20, 30 mg/kg), mercuric chloride (HgCl2, 0.5, 0.75, 1.0 mg/kg), folic acid (125, 350, 375 mg/kg), ethyleneimine (0.5, 2.0, 5.0 microliters/kg). Bovine serum albumin (BSA) was injected by the same method, twice daily on 3 consecutive days (2.5, 7.14 g/kg). The results obtained indicate a characteristic dose- and time-dependent pattern of excreted enzyme activities for each of the tested compounds. In both models with primarily glomerular damage, proximal tubular parts were also affected, as could be demonstrated by increased urinary GST and histopathological changes. Damage, mainly to the S1/S2 segment by 20 or 30 mg Na2 CrO4/kg, resulted in moderate to marked increases in LDH excretion, while GST was only moderately elevated at 30 mg/kg. Extreme increases in GST and LDH output were measured after predominant S3 segment damage after 0.75 and 1.0 mg HgCl2/kg. The distally active compounds, folic acid and ethyleneimine, did not increase GST excretion at lower doses. At the high doses, a small rise in GST excretion indicated some, probably secondary, proximal tubular involvement, which correlated with the histopathological findings in these groups.

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“…In addition, GSH‐S‐Ts may act as binding proteins either covalently or noncovalently with a variety of compounds ( Ketley et al ., 1975 ). GSH‐S‐Ts have been reported in a number of different tissues including liver, kidney, lung, placenta, epididymis, and mammary gland ( Guthenberg & Mannervik, 1979; Guthenberg et al ., 1979 ; Hales et al ., 1978 , 1980; Puente et al ., 1982 ). Also, nuclear, microsomal and cytosolic forms have been identified ( Morgenstern et al ., 1982 ; Hayes & Mantle, 1986; Ketterer et al ., 1990 ).…”

Section: Introductionmentioning

confidence: 99%

Influence of age, hormones and germ cells on glutathione S‐transferase activity in cultured Sertoli cells

Castellón

1999

Int J of Andrology

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Glutathione S-transferase (GSH-S-T) activity was measured, using 1-Cl-2,4-dinitrobenzene as substrate, in Sertoli cell cultures obtained from rats aged 10, 18, and 26 days. The GSH-S-T activity showed a significant increase with age of the Sertoli cell donor. When cultures were treated with hypotonic solution, in order to eliminate residual contaminating germ cells, the age dependent increase in enzyme activity was less pronounced. FSH, but not testosterone, increased enzyme activity in all cultures. Addition of freshly isolated germ cells (mainly pachytene spermatocytes) to hypotonic-treated Sertoli cell monolayers enhanced GSH-S-T activity at all ages. It is concluded that GSH-S-T activity can be measured in cultured Sertoli cells during the period of onset of spermatogenesis (10-26 days). This enzyme activity is dependent on age of the Sertoli cell donor and is influenced by FSH and germ cells. Since GSH-S-Ts are actively engaged in cell detoxificative functions through conjugation of xenobiotics with glutathione, the present findings suggest that this enzyme may have a relevant protective role during the critical period when spermatogenesis is being established.

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Isoelectric Focusing of Glutathione S-Transferases From Rat Liver and Kidney

Cited by 4 publications

References 14 publications

High‐affinity binding of fatty acyl‐CoAs and peroxisome proliferator‐CoA esters to glutathione S‐transferases

High‐affinity binding of fatty acyl‐CoAs and peroxisome proliferator‐CoA esters to glutathione S‐transferases

Determination of urinary glutathione S-transferase and lactate dehydrogenase for differentiation between proximal and distal nephron damage

Influence of age, hormones and germ cells on glutathione S‐transferase activity in cultured Sertoli cells

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