A cDNA clone encoding amorpha-4,11-diene synthase from Artemisia annua was subcloned into a bacterial expression vector in frame with a His6-tag. Recombinant amorpha-4,11-diene synthase was produced in Escherichia coli and purified to apparent homogeneity. The enzyme showed pH optimum at pH 6.5, and a minimum at pH 7.5. Substantial activity was observed in the presence of Mg2+, Mn2+ or Co2+ as cofactor. The enzyme exhibits a low activity in the presence of Ni2+ and essentially no activity with Cu2+ or Zn2+. The sesquiterpenoids produced from farnesyl diphosphate in the presence of Mg2+ were analyzed by GC-MS. In addition to amorpha-4,11-diene, 15 sesquiterpenoids were produced. Only small quantitative differences in product pattern were observed at pH 6.5, 7.5, or 9.5. Amorpha-4,11-diene synthase showed significant increased product selectivity in the presence of Mn2+ or Co2+. Km for farnesyl diphosphate was 3.3, 8.0, and 0.7 microM in the presence of Mg2+, Mn2+ or Co2+, respectively. The corresponding kcat-values were 6.8, 15.0, and 1.3 x 10(-3) s(-1), respectively. Km and kcat for geranyl diphosphate were 16.9 microM and 7.0 x 10(-4) s(-1), respectively, at pH 6.5, in the presence of Mn2+.
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http://dx.doi.org/10.1016/j.abb.2005.02.012 | DOI Listing |
J Agric Food Chem
January 2025
College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009, China.
Phytoene synthase (PSY) is one of key enzymes in carotenogenesis that catalyze two molecules of geranylgeranyl diphosphate to produce phytoene. PSY is widespread in bacteria, archaea, and eukaryotes. Currently, functional role and catalytic mechanism of archaeal PSY homologues have not been fully clarified due to the limited reports.
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Department of Urology, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Henan University People's Hospital, Zhengzhou, 450003, China.
Background: Bladder cancer is one of the most common malignancies of the urinary system. Despite significant advances in diagnosis and treatment, the compromised therapeutic effect of chemotherapeutic agents, such as Oxaliplatin (OXA), remains a major clinical challenge. Thus, a combination therapy is required to enhance the OXA's therapeutic effectiveness and improve patient outcomes.
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January 2025
Animal and Poultry Production Division, Department of Animal and Poultry Breeding, Desert Research Center, Cairo, Egypt.
Brucellosis is a highly contagious zoonotic bacterial disease. It has considerable negative consequences on the animal production industry worldwide. The objective of this study was to investigate the genetic and molecular variations in Shami goat susceptible to Brucella infection.
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January 2025
Department of Pesticide Chemistry, National Research Centre, Dokki, 12622, Giza, Egypt.
Chemoprevention is one of the accessible strategies for preventing, delaying or reversing cancer processing utilizing chemical intervention of carcinogenesis. NAD(P)H quinone oxidoreductase 1 (NQO1) is a xenobiotic metabolizing cytosolic enzyme/protein with important functional properties towards oxidation stress, supporting its ability in detoxification/chemoprotective role. A set of 3,5-diylidene-4-piperidones (as curcumin mimics) bearing alkyl sulfonyl group were synthesized with potential NQO1 induction properties.
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Helmholtz International Lab for Anti-infectives, Shandong University-Helmholtz Institute of Biotechnology, Shandong University, Qingdao, Shandong, China.
Modular polyketide synthases (mPKSs) are multidomain enzymes in bacteria that synthesize a variety of pharmaceutically important compounds. mPKS genes are usually longer than 10 kb and organized in operons. To understand the transcriptional and translational characteristics of these large genes, here we split the 13-kb busA gene, encoding a 456-kDa three-module PKS for butenyl-spinosyn biosynthesis, into three smaller separately translated genes encoding one PKS module in an operon.
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