• BMB Reports
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• v.40 no.6
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• pp.861-869
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• 2007

The enzyme 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR; EC1.1.1.34) catalyzes the first committed step of isoprenoids biosynthesis in MVA pathway. Here we report for the first time the cloning and characterization of a full-length cDNA encoding HMGR (designated as CgHMGR, GenBank accession number EF206343) from hazel (Corylus avellana L. Gasaway), a taxol-producing plant species. The full-length cDNA of CgHMGR was 2064 bp containing a 1704-bp ORF encoding 567 amino acids. Bioinformatic analyses revealed that the deduced CgHMGR had extensive homology with other plant HMGRs and contained two transmembrane domains and a catalytic domain. The predicted 3-D model of CgHMGR had a typical spatial structure of HMGRs. Southern blot analysis indicated that CgHMGR belonged to a small gene family. Expression analysis revealed that CgHMGR expressed high in roots, and low in leaves and stems, and the expression of CgHMGR could be up-regulated by methyl jasmonate (MeJA). The functional color assay in Escherichia coli showed that CgHMGR could accelerate the biosynthesis of $\beta$-carotene, indicating that CgHMGR encoded a functional protein. The cloning, characterization and functional analysis of CgHMGR gene will enable us to further understand the role of CgHMGR involved in taxol biosynthetic pathway in C. avellana at molecular level.

• Korean Journal Plant Pathology
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• v.12 no.3
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• pp.285-290
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• 1996

3-hydroxy-3-methyglutaryl coenzyme A reductase (HMGR)는 phytoalexin을 포함하는 수 많은 isoprenoid화합물의 생합성을 조절하는 효소이다. 토마토의 경우 sesquiterpenoid phytoalexin류가 식물방어를 위한 반응산물로서 축적되는 것이 알려져 있다. Verticil-lium albo-atrum이나 Fusarium oxysporum으로부터 추출한 elicitor를 토마토의 배양세포에 처리하는 경우 처리량의 증가에 따른 2.7kb 크기의 HMGR mRNA의 상당한 유도증가가 토마토의 HMG2 DNA를 이용한 northern hybridization에 의해 관찰되었다. 토마토의 잎, 뿌리, 줄기 등에 기계적 상해를 가하는 경우에서도 HMGR mRNA는 2단계를 걸쳐 증가함이 관찰되었다. HMGR mRNA는 양 실험의 경우 모두 9시간에서 12시간 사이에서 최대발현됨이 관찰되었다.

• Plant Biotechnology Reports
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• v.5 no.1
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• pp.53-60
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• 2011

Artemisinin is effective against both chloroquine-resistant and -sensitive strains of Plasmodium species. However, the low yield of artemisinin from cultivated and wild plants is a serious limitation to the commercialization of this drug. Optimization of artemisinin yield either in vivo or in vitro is therefore highly desirable. To this end, we have overexpressed the 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGR) gene (hmgr) from Catharanthus roseus L. in Artemisia annua L. and analyzed its influence on artemisinin content. PCR and Southern blot analyses revealed that the transgenic plants showed stable integration of the foreign hmgr gene. The reverse transcriptase-PCR results suggested that the hmgr was expressed at the transcriptional level in transgenic lines of Artemisia annua L., while the high-performance liquid chromatography analysis showed that artemisinin content was significantly increased in a number of the transgenic lines. Artemisinin content in one of the A. annua transgenic lines was 38.9% higher than that in non-transgenic plants, and HMGR enzyme activity in transgenic A. annua L. was also higher than that in the non-transgenic lines.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1995.06b
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• pp.55-75
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• 1995

Induction of HMG-Co A reductase (HMGR) is essential for the biosynthesis of sesquiterpenoid phytoalexins and steroid derivatives in Solanaceous plants following wounding and pathogen infection. To better understand this complex step in stress-responsive isoprenoid synthesis, three classes of cDNAs for HMGR (hmg1, hmg2, and hmg3) were isolated from a potato tuber library. The potato cDNAs had extensive homology in open reading frames but had low homology in the 3'-untranslated regions. RNA gel blot analysis using gene-specific probes revealed that hmg1 is induced by wounding but wound induction is strongly suppressed by arachidonic acid or by inoculation with Phytophthora infestants. In contrast, hmg2 and hmg3 are slightly induced by wounding and strongly enhanced by arachidonic acid or inoculation. The induction and suppression of HMGR genes parallel the suppression of steroid and stimulation of sesquiterpenoid accumulations observed in earlier investigations. Treatment of the tuber disks with a low concentration of methyl-jasmonate doubled the wound induced accumulation of hmg1 transcripts and steroid-glycoalkaloid accumulation, but did not affect the abundance of transcripts for hmg2 or hmg3 nor induce phytoalexins. High concentration of methyl-jasmonate suppressed hmg1 mRNA and steroid-glycoalkaloid accumulation, induced hmg3 mRNA, and did not elicit phytoalexins. Lipoxygenase inhibitors suppressed the accumulation of of hmg1 transcripts and steroid-glycoalkaloids, which were restored by exogeneous methyl-jasmonate. Methyl-jasmonate applied together with arachidonic acid enhanced the elicitor induced accumulation of sesquiterpenes and sustained steroid-glycoalkaloid levels with transcript levels for the various HMGR mRNAs equal to or greater than wound-only treatment. These results domonstrate that the consequences of wound- and pathogen-responses of plants are different at the levels of gene expression and associated secondary metabolism.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.727-731
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• 2005

Synthesized Ile-Ala-Val-Pro (IAVP) peptide, which has the highest hypocholesterolemic effect among a number of synthesized derivatives of Ile-Ala-Val-Pro-Gly-Glu-Val-Ala (IAVPGEVA) isolated from 11S globulin of soy protein by pepsin digestion, was selected for investigation in the present study. Using a recombinant Syrian hamster 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), we studied in detail the inhibition of this enzyme by IAVP and compared the action of this peptide to that of lovastatin, a known competitive inhibitor of this enzyme. The concentration of IAVP required for 50% inhibition ($IC_{50}$) of HMGR activity in given experimental conditions was $340\;{\mu}M$. Kinetic analysis revealed that the studied peptide is a competitive inhibitor of HMGR with respect to both 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) and nicotinamide adenine dinucleotide phosphate (NADPH), with an equilibrium constant of inhibitor binding ($K_i\;=\;[E][I]/[EI]$) of $61{\pm}1.2\;{\mu}M$ and $157{\pm}4.4\;{\mu}M$, respectively. At the same conditions, $K_i$ and $IC_{50}$ for lovastatin were $2.2{\pm}0.1\;nM$ and 12.5 nM, respectively. Thus, the given peptide interacts with HMGR as a bisubstrate, consequently blocking access of both substrates to the active sites. The achieved results suggest the design of new peptide sequences having a higher relative affinity to binding sites of this enzyme and an enhancement of their hypocholesterolemic properties.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.279-283
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• 2006

This study was conducted to examine the effect of polyphenols from safflower seed on HMG-CoA reductase (HMGR) activity, LDL oxidation and Apo A1 secretion from Hep3B cell. The safflower seed polyphenols were matairesinol (Iignan), enterolactone (lignan metabolite), acacetin (flavone) and serotonin derivative. In addition to safflower polyphenols, mevastatin, ${\alpha}-estradiol,\;{\alpha}-tocopherol$ and soy genistein were tested as reference compounds depending on the type of the test. HMGR source was liver microsome obtained from rat fed 2% cholestyramine for 10 days. Inhibition of HMGR activity was greater with mevastatin (53%) than safflower serotonin derivatives (45%), followed by genistein (35%), but was very small with matairesinol, enterolactone and acacetin. LDL oxidation induced by $CuSO_4$ was suppressed by all the test material used in the present study and in the order of safflower serotonin derivatives> matairesinol > ${\beta}-estradiol$ > genistein > acacetin > enterolactone. Apo A1 secretion from Hep3B cell was significantly stimulated by mevastatin, but moderately (p<0.1) by ${\beta}-estradiol$ and genistein as well as enterolactone. These results suggest that the safflower polyphenols improve body lipid status via inhibition of cholesterol synthesis and suppression of LDL oxidation.

• Journal of Applied Biological Chemistry
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• v.42 no.2
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• pp.92-96
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• 1999

To study the regulatory mechanism of isoprenoid (carotenoid) biosynthesis, we have compared the expression patterns of nine isoprenoid biosynthetic genes in Korean red pepper (Capsicum. annuum cv. NocKaung). The expression of geranylgeranyl pyrophosphate synthase gene was initially induced at early ripening stage (I1) and was rather slightly decreased during pepper fruit ripening. The ex-pression of phytoene synthase gene was strongly induced at semi-ripening stage (I2) and the phytoene desaturase transcript was maximally induced at the fully ripened stage (R). Our results suggest that genes encoding two 3-hydroxy-3-methylglutaryl-CoA reductase isozymes (HMGR1 and HMGR2) and farnesyl pyrophosphate synthase might be not so critical in pepper carotenoid biosynthesis but three genes encoding geranylgeranyl pyrophosphate synthase, phytoene synthase and phytoene desaturase were induced in a sequential manner and coordinately regulated during the ripening of pepper fruit.

• Proceedings of the Botanical Society of Korea Conference
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• 1994.07a
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• pp.111-136
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• 1994

• Journal of Nutrition and Health
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• v.38 no.4
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• pp.267-278
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• 2005

Postmenopausal women or ovariectomized rats are associated with increased cholesterol levels, which are risk factors of metabolic syndrome and cardiovascular diseases. Increased prevalence of metabolic syndrome after menopause might be associated with estradiol deficiency. Harmful effect of estradiol hampers the casual usage of hormone to prevent the metabolic syndrome. Soy protein has been reported to show several beneficial effects on health, however it is unclear which components of soy protein is responsible for anti-obesity and hypocholesterolemic effects. Soy isoflavones, gem-stein and daizein, are suggested to have anti-obesity and hypocholesterolemic effects but with inconsistency. The present study investigated the effect of supplementation of genistein (experiment I) and soy protein containing isoflavones (experiment II) to high fat diet on body weight gain, food intake, liver and fat tissue weight and the lipid levels in ovariectomized rats. Plasma and hepatic lipid contents and the mRNA levels of genes encoding lipid metabolism related proteins, such as CPT1 and HMGR were measured. Ovariectomy increased body weight, fat tissue weight and plasma and hepatic lipid levels which increase the risk of metabolic syndrome. Soy protein could improve plasma and hepatic lipids levels. Soy protein also increased hepatic CPT1 and HMGR mRNA levels. Plasma and hepatic lipids levels could not be decreased by dietary genistein alone. In contrast, lipids levels could be decreased by isoflavone-fortified soy protein, suggesting that the ingestion of soy protein enriched with isoflavone gives more benefit for protecting postmenopausal women from metabolic syndrome.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2012.05a
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• pp.20-20
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• 2012

Isoprenoids represent the most diverse group of metabolites, which are functionally and structurally identified in plant organism to date. Ginsenosides, glycosylated triterpenes, are considered to be the major pharmaceutically active ingredient of ginseng. Its backbones, categorized as protopanaxadiol (PPD), protopanaxatriol (PPT), and oleanane saponin, are synthesized via the isoprenoid pathway by cyclization of 2,3-oxidosqualene mediated with dammarenediol synthase or beta-amyrin synthase. The rate-limiting 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), which is the first committed step enzyme catalyzes the cytoplasmic mevalonate (MVA) pathway for isoprenoid biosynthesis. DXP reductoisomerese (DXR), yields 2-C-methyl-D-erythritol 4-phosphate (MEP), is partly involved in isoprenoid biosynthesis via plastid. Squalene synthase and squalene epoxidase are involved right before the cyclization step. The triterpene backbone then undergoes various modifications, such as oxidation, substitution, and glycosylation. Here we will discuss general biosynthesis pathway for the production of ginsenoside and its modification based on their subcellular biological functions.