• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.365-372
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• 1997

Biochemical characteristics and activities of glutathione-S-transferases(GSTs) and carboxylesterase extracted from soybean and corn plants treated with quizalofop-ethyl were investigated. Km value and Vmax of GSTs extracted from soybean and corn plants were $6.7{\times}10^{-3}M$ nmole/mg/min, 50, 20 nmole/mg/min, respectively. Optimum pH of carboxylesterase from soybean and corn was 7.0. Km value and Vmax of carboxylesterase extracted from soybean and corn plants were $4.2{\times}10^{-4}M$, $2.5{\times}10^{-4}M$ nmole/mg/min, 33, 10 nmole/mg/min, respectively. GSTs and carboxylesterase activity were reduced by quizalofop-ethyl. GSTs and carboxylesterse activity of corn was more reduced than that of soybean. When soybean and corn were treated by 80 ppm of quizalofopethyl. Soybean recovered after 10 days elapsing, but corn withered after 3days elapsing.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.71-71
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• 1993

Carboxylesterase is widely distributed in the tissues of vertebrates, insects, plants and mycobacteria. Among various tissues of animals and humans, the highest esterase activity with various substrates is found in the liver. Kidney has moderate carboxylesterase activity in the proximal tubules. Considerable esterase activity is also found in the small intestine epithet elial cells and serum of mammals. Besides these tissues, carboxylesterase has been found in the lung, testis, adipose tissue, nasal mucosa and even in the central nervous system. Hepatic microsomal carboxylesterase catalyzes the hydrolysis of a wide variety of endogenous and exogenous compounds such as carboxylester, thioester and aromatic amide. Since carboxylesterases are important for metabolic activation of prodrugs and detoxification of xenobiotics, differences in substrate specificity and immunological properties of this enzyme are important in connection with choosing a suitable laboratory animal for the evaluation of biotransformation and toxicity of drugs. On the other hand, liver, kidney, intestine and serum were found to contain multiple forms of carboxylesterases in animal species and humans. In fact, we have purified more than fifteen isoforms of carboxylesterases from microsomes of liver, kidney and intestinal mucosa of nine animal species and humans. and characteristics of these isoforms were compared each other in terms of their physical and immunochemical properties. On the other hand, we have reported that hepatic microsomal carboxylesterases are induced by many exogenous compounds such as phenobarbital, polycyclic aromatic hydrocarbons, Aroclor 1254, aminopyrine and clofibrate. Later, we showed that some isoforms of hepatic carboxylesterase were induced by glucocorticoids such as dexamethasone and 16 ${\alpha}$-carbonitrile, but other isoforms were rather inhibited by these compounds. These findings indicate that involvement of carboxylesterases in the metabolism and toxicity of drugs should be explained by the isoforms involved. Since 1991, we have carried out detailed research investigating the types of carboxylesterases involved in the metabolic activation of CPT-11, a derivative of camptothecin, to the active metabolite, SN-38. The results obtained strongly suggest that some isoforms of carboxylesterase of liver microsomes and intestinal mucosal membrane are exclusively involved in CPT-11 metabolism. In this symposium, the properties of carboxylesterase isoforms purified from liver, kidney and intestine of animal species and humans are outlined. In addition, metabolism of CPT-11, a novel antitumor agent, by carboxylesterases in relation to the effectiveness will also be discussed.

• Biomolecules & Therapeutics
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• v.17 no.4
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• pp.335-347
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• 2009

This review covers current developments in molecular-based studies of the structure and function of carboxylesterases. To allay the confusion of the classic classification of carboxylesterase isozymes, we have proposed a novel nomenclature and classification of mammalian carboxylesterases on the basis of molecular properties. In addition, mechanisms of regulation of gene expression of carboxylesterases by xenobiotics, and involvement of carboxylesterase in drug metabolism are also described.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.71-79
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• 1998

Haemolyph carboxylesterases induced in diapausing pupae of Helicoverpa assulta Guenee were investigated. Increase in the activity of the electrophoresed isozyme bands were observed during the diapausing pupae. The isozymatic composition exhibited remarkable alterations represented as disappearance and induction of some isozyme bandsp which were identified as carboxylesterase (CE) on the basis of their specificities to inhibitors. Much higher activity of the induced CE was shown in reaction with $\beta$-naphthyl acetate ($\beta$-Na) than $\alpha$-naphthyl butyrate ($\alpha$-Nb), representing the high regioselectivity to $\beta$-naphthyl group. Optimal temperature for the enzyme activity was different to the substrates used 37$^{\circ}C$ in $\beta$-Na and 4$0^{\circ}C$ in $\alpha$-Nb, respectively. However, the optimal pH for the enzyme activity was the same as 7.5 regardless of the substrates used, and relatively high thermostability of the CE was demonstrated by showing the denaturation at high temperature (50~55$^{\circ}C$).

• BMB Reports
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• v.32 no.4
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• pp.331-338
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• 1999

Ethanol catabolism is thought to produce metabolic disorders resulting in alcoholic liver disease. To investigate the mutual effects of ethanol catabolism and cholestasis induced by common bile duct ligation on the activities of carboxylesterase, we have determined the enzyme activities in rat hepatic (cytosolic, mitochondrial, and microsomal) preparations as well as in rat serum using ten animal models: normal rats (group 1), sham-operated rats (group 2), common bile duct-ligated rats (group 3), ethanol-intoxicated rats (group 4), sham-operation plus chronic ethanol-intoxicated rats (group 5), common bile duct-ligated plus chronic ethanol-intoxicated rats at 1.5h and 24h (groups 7A and 7B), and duct-ligated and acute ethanol intoxicated rats at 1.5 h and 24 h (groups 8A and 8B). The $K_m$ and $V_{max}$ values of carboxylesterase from these hepatic preparations of cholestatic rat liver combined with chronic ethanol intoxication were also measured by using ethyl valerate as the substrate from the 14th day post-ligation. Carboxylesterase activities of all hepatic preparations and rat serum (group 3) showed significant decreases compared to the activities from the sham-operated control (group 2). Enzyme kinetic parameters indicated that $V_{max}$ of carboxylesterase from all the hepatic preparations in cholestatic rats (group 3) decreased significantly, although the $K_m$ values were about the same as in the sham-operated control (group 2). When cholestasis was combined with chronic ethanol intoxication (group 6), carboxylesterase activities showed further decrease in all the hepatic preparations and serum compared to the control activity (group 5). The $V_{max}$ also decreased significantly, although $K_m$ values did not change. When common bile duct ligation was combined with acute ethanol intoxication (group 8), the enzyme activities in the rat liver and serum showed significant decrease compared to the activity from acute ethanol-intoxicated rats (group 7). However, quite contrary to this, the activities of serum from acute ethanol intoxication 1.5 h (group 7A) increased significantly compared to the activities in the normal control (group 1). These results, therefore, suggest that the biosynthesis of hepatic carboxyl-esterase seems to decrease when cholestasis is combined with chronic and acute ethanol intoxication, and the decrease in activity is more significant than from cholestasis alone.

• Applied Biological Chemistry
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• v.36 no.1
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• pp.64-69
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• 1993

This study was performed to investigate detoxifying enzyme activities of carboxylesterase(CE), glutathione S-transferase(GST) and lactate dehydrogenase(LDH) at variable toxicity levels in fresh water fish, carp(Cyprinus carpio L.). The carp was exposed to single and combined pesticides of IBP, isoprothiolane and cartap for 48 hr at sublethal doses, $LC_{10}$ and $LC_{26}$. The detoxifying enzyme activities were assayed for the liver, head and gut of the carp. The enzyme activities we discovered were as follows: Both activities of CE and GST were increased at the sublethal doses but were declined by increasing doses. In the gut, we found that the CE activity had high levels in the treatment groups of isoprothiolane+IBP and isoprothiolane+cartap. In the head, the CE activity had high levels in the treatment groups of cartap, IBP and isoprothiolane. However, the GST activities were inconsistent in the head and gut of the fish. Also, the GST activity was declined by increasing protein contents. The highest LDH activity was shown in the isoprothiolane treated fish, while the lowest activity was observed in the isoprothiolane+cartap treatment.

• Journal of Microbiology and Biotechnology
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• v.19 no.2
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• pp.147-154
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• 2009

The carboxylesterase-encoding gene(bioHs) of a newly isolated strain, Serratia sp. SES-01, was cloned from the genomic DNA library by detecting formation of transparent halo around the colony on LB-tributyrin agar plates. The amino acid sequence of BioHs was highly similar to the members of the BioH enzyme family involved in the biotin biosynthetic pathway; it showed the highest similarity(91%) with that of Serratia proteamaculans. To compare BioHs with other BioH enzymes, the relatively well-known bioHe gene of E. coli was cloned with PCR. After we achieved high-level expression of soluble BioHs and BioHe through the exploration of different culture conditions, the purified BioHs and BioHe enzymes were characterized in terms of specificity, activity, and stability. BioHe was generally more robust to a change in temperature and pH and an addition of organic solvents than BioHs. The two enzymes exhibited a strong preference for carboxylesterase rather than for thioesterase and were optimal at relatively low temperatures($20-40^{\circ}C$) and alkaline pHs(7.5-9.0). The results in this study strongly suggested that both the BioHs and BioHe enzymes would be potential candidates for use as a carboxylesterase in many industrial applications.

• The Plant Pathology Journal
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• v.32 no.4
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• pp.347-356
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• 2016

Plants protect themselves from pathogen attacks via several mechanisms, including hypersensitive cell death. Recognition of pathogen attack by the plant resistance gene triggers expression of carboxylesterase genes associated with hypersensitive response. We identified six transcripts of carboxylesterase genes, Vitis flexuosa carboxylesterase 5585 (VfCXE5585), Vf-CXE12827, VfCXE13132, VfCXE17159, VfCXE18231, and VfCXE47674, which showed different expression patterns upon transcriptome analysis of V. flexuosa inoculated with Elsinoe ampelina. The lengths of genes ranged from 1,098 to 1,629 bp, and their encoded proteins consisted of 309 to 335 amino acids. The predicted amino acid sequences showed hydrolase like domains in all six transcripts and contained two conserved motifs, GXSXG of serine hydrolase characteristics and HGGGF related to the carboxylesterase family. The deduced amino acid sequence also contained a potential catalytic triad consisted of serine, aspartic acid and histidine. Of the six transcripts, Vf-CXE12827 showed upregulated expression against E. ampelina at all time points. Three genes (VfCXE5585, VfCXE12827, and VfCXE13132) showed upregulation, while others (VfCXE17159, VfCXE18231, and VfCXE47674) were down regulated in grapevines infected with Botrytis cinerea. All transcripts showed upregulated expression against Rhizobium vitis at early and later time points except VfCXE12827, and were downregulated for up to 48 hours post inoculation (hpi) after upregulation at 1 hpi in response to R. vitis infection. All tested genes showed high and differential expression in response to pathogens, indicating that they all may play a role in defense pathways during pathogen infection in grapevines.

• YAKHAK HOEJI
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• v.39 no.4
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• pp.450-460
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• 1995

The acute toxicity of fthalide in rat was studied in vivo by the observations of the changes in hematogram, serological parameters, content of cytochrome p-450, activities of NADPH-cytochrom c reductase, glucose-6-phosphatase, and the contents of cholinesterase and carboxylesterase in liver. Fthabde is a practically non-toxic substance(LD50 is 3.86g/kg), but rats were intoxicated with fthabde at a oral dose of 100 mg/kg for 12 days. WBC were significantly decreased and activities of ALT and LDH, on the cotrary, the content of glucose in serum were slightly increased. Cytochrome p-450 and lipid peroxide in liver were significantly increased in the fthalide-intoxicated rats. The longer administration of fthalide showed further increase of carboxylesterase activity in liver and serum, but decrease of activities of glucose-6-phosphatase and cholinesterase in liver and serum. These results show that fthatide can induce the hepatocellular injury and neurotoxicity.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.3
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• pp.131-137
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• 2020

The present study investigated effects of antifungal and carboxylesterase inoculant on rumen fermentation with different rumen pH. Corn silage was treated without inoculant (CON) and with a mixed Lactobacillus brevis 5M2 and L. buchneri 6M1 (MIX). Rumen fluid was collected from two cannulated Hanwoo heifers before morning feeding (high rumen pH at 6.70) and 3 h after feeding (low rumen pH at 6.20). Dried corn silage was incubated in the rumen buffer (rumen fluid + anaerobic culture medium at 1:2 ratio) for 48 h at 39℃. Eight replications for each treatment were used along with two blanks. Both in a high and a low rumen pH, MIX silages presented higher (p<0.05) the immediately degradable fraction, the potentially degradable fraction, total degradable fraction, and total volatile fatty acid (VFA) than those of CON silages. Incubated corn silages in a low rumen pH presented lower (p<0.05) total degradable fraction, ammonia-N, total VFA (p=0.061), and other VFA profiles except acetate and propionate, than those in a high rumen pH. The present study concluded that application of antifungal and carboxylesterase inoculant on corn silage could improve degradation kinetics and fermentation indices in the rumen with high and low pH conditions.