• BMB Reports
• /
• v.38 no.2
• /
• pp.232-237
• /
• 2005

A glutathione S-transferase (GST) from Lactuca sativa was purified to electrophoretic homogeneity approximately 403-fold with a 9.6% activity yield by DEAE-Sephacel and glutathione (GSH)-Sepharose column chromatography. The molecular weight of the enzyme was determined to be approximately 23,000 by SDS-polyacrylamide gel electrophoresis and 48,000 by gel chromatography, indicating a homodimeric structure. The activity of the enzyme was significantly inhibited by S-hexylGSH and S-(2,4-dinitrophenyl) glutathione. The enzyme displayed activity towards 1-chloro-2,4-dinitrobenzene, a general GST substrate and high activities towards ethacrynic acid. It also exhibited glutathione peroxidase activity toward cumene hydroperoxide.

• Analytical Science and Technology
• /
• v.10 no.5
• /
• pp.378-385
• /
• 1997

In order to clarify the functional role of Tyr7 in human glutathione S-transferase P1-1, we extensively investigated the effect of mutation of Tyr7 on the substrate specificity and inhibition characteristics. The mutational replacement of Tyr7 with phenylalanine lowered the specific activities with 1,2-dichloro-4-nitrobenzene and 1,2-epoxy-3-(p-nitrophenoxy) propane for GSH-conjugation reaction to 3~5% of the values for the wild-type enzyme. The pKa of the thiol group of GSH bound in Y7F was about 2.4 pK units higher than that in the wild-type enzyme. The $I_{50}$ of hematin for Y7F was similar to that for the wild-type enzyme and those of benastatin A and S-(2,4-dinitrophenyl)glutathione were only moderately decreased. These results suggest that Tyr7 is considered to be important the catalytic activities not only for GSH-chloronitrobenzene derivatives but also for GSH-epoxide conjugation reaction, rather than to binding of the substrates.

• The Korean Journal of Pesticide Science
• /
• v.10 no.1
• /
• pp.50-55
• /
• 2006

A field-resistant strain of the diamondback-moth(Plutella xylostella L.), collected from Chinese cabbage alpine farmland at Gangwon-do, Korea, was used for determination of the characteristics of resistance to chlorpyrifos using the activities of esterases and glutathione-S-transferase(GST), protein sequestration and AChE insenstivity. Although the activities of esterases extracted from resistant strain and susceptible strain were not significantly different, isozyme bands shown on the electrophoresis were different. GST activity from field resistant strain was 1.5-fold higher than that of susceptible. No differences were shown between resistant and susceptible ones in protein sequestration. The insensitivities of AChE to chlorpyrifos, however, extracted from susceptible strain was 460-fold higher than those of resistant. These results indicated that the insensitivity of AChE is the major factor for developing the resistance and activities of GST might be a minor factor.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.20 no.3
• /
• pp.203-208
• /
• 1991

The present study was undertaken in order to elucidate the effects of pretreatment with nicotinamide on changes in the hepatic metabolizing enzyme system inducted by streptozotocin (STZ). In rats, STZ(50mg/kg) administered by tail vein caused a significant rise in hepatic aniline hydroxylase and a decrease in aminopyrine N-demethylase when compared to control (p<0.05). Pretreatment with nicotinamice inhibited these effects (p<0.05). Similarly, STZ induced changes in hepatic microsomal cytochrome P-450 activity were inhibited by pretreatment with nicotinamide (p<0.05). However, changes in UDP-glucuronyl transferase and sulfortransferase activity were not significantly different(p>0.05). Pretreatment with nicotinamide also prevented STZ induced increases in glutathion S-tranferase activity when compared to the control(p<0.05). There results suggest that nicotinamide pretreatment suppresses STZ-induced changes in the hepatic metabolizing enzyme system.

• Analytical Science and Technology
• /
• v.22 no.3
• /
• pp.228-234
• /
• 2009

To gain further insight into herbicide detoxification of plant, we purified a glutathione S-transferase from Brassica oleracea (BoGST) and studied its substrate specificity towards several xenobiotic compounds. The BoGST was purified to electrophoretic homogeneity with approximately 10% activity yield by DEAE-Sephacel and GSHSepharose column chromatography. The molecular weight of the BoGST was determined to be approximately 23,000 by SDS-polyacrylamide gel electrophoresis and 48,000 by gel chromatography, indicating a homodimeric structure. The activity of the BoGST was significantly inhibited by S-hexyl-GSH and S-(2,4-dinitrophenyl)GSH. The substrate specificity of the BoGST displayed high activities towards CDNB, a general GST substrate and ethacrynic acid. It also exhibited GSH peroxidase activity toward cumene hydroperoxide.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.28 no.2
• /
• pp.85-91
• /
• 2014

This study was designed to find out the effect of Nosema spore on oxidative damages and antioxidant defence in the midgut of tasar silkworm Antheraea mylitta. Higher level of lipid peroxidation (LPX) and total hydroperoxides indicate the resultant oxidative stress in the Nosema exposed specimen. Increased superoxide dismutase (SOD) suggests activation of physiological mechanism to scavenge the superoxide radical produced during Nosema infection. Higher activities of catalase and glutathione-S-tranferase on $18^{th}$ d indicate adaptive behaviour of the tissue against oxyradicals. The results suggest that Nosema infection is involved in altering the active oxygen metabolism by modulating LPX and reactive oxygen species (ROS), which is indicative of pebrine disease disorder.

• The Korean Journal of Pharmacology
• /
• v.21 no.1
• /
• pp.1-11
• /
• 1985

The effects of feeding indole, indole-3-carbinol and benzofuran (all at 5 mmole/kg body wt./day) on various hepatic microsomal and cytosolic enzyme activities involved in xenobiotic metabolism have been compared. Benzofuran was found to elevate the activities of many enzymes both in microsomes (e.g., aniline hydroxylase, 7-ethoxycoumarin O-deethylase, p-nitrophenol UDPGA-transferase and epoxide hydrolase) and in cytosol (e.g., glutathione reductase, glutathione S-transferase, NADH:quinone reductase and UDP-glucose dehydrogenase). The structures of indole and indole-3-carbinol are similar to benzofuran except for the substitution of nitrogen with oxygen atom within the furan ring. Results showed that the activities of UDPGA-transferase and NADH:quinone reductase were not elevated by these indole compounds. While the chemical structure of these two indole compounds are identical except for the presence of the carbinol (methanol) group in indole-3-carbinol, there were marked differences in the types and activities of microsomal enzymes that were enhanced. Among the microsomal enzyme activities determined, indole elevated only the NADPH:cytochrome c reductase, while indole-3-carbinol increased several mixed function oxidase and particularly the epoxide hydrolase activities. Based on the chemical structures of tested compounds and the observed results, possible explanations for the mechanisms involved in elevating epoxide hydrolase activity by benzofuran and indole-3-carbinol are discussed.

• Korean Journal of Clinical Pharmacy
• /
• v.16 no.2
• /
• pp.155-164
• /
• 2006

Great inter-variability in drug response and adverse drug reactions is related to inter-variability of drug bioavailability, drug interaction and patient's disease and physyological state that cause change in absorption, distribution, metabolism and excretion of drugs. However, these alone do not sufficiently predict and explain inter-variability in drug response. In recent studies, it is reported that inter-variability in drug response and adverse drug reactions may largely resulted from genetically determined differences in drug absoption, distribution, metabolism and drug target proteins. Especially, the major human drug-metabolizing enzymes such as CYP450, N-acetyl tranferase, thiopurine S-methyl transferase, glutathione S-transferase are identified as the major gene variants that cause inter-individual variability in drug's response and adverse drug reactions. These variations may have most significant implications for those drugs that have narrow therapeutic index and serious adverse drug reactions. Therefore, the genetic variation such as polymorphisms in drug metabolizing enzymes can affect the response of individuals to drugs that are used in the treatment of depression, psychosis, cancer, cardiovascular disorders, ulcer and gastrointestinal disorders, pain and epilepsy, among others. This review describes the pharmacogenomics of the drug metabolizing enzymes associated with the drug response and its clinical applications.