• Animal cells and systems
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• v.10 no.4
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• pp.197-201
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• 2006

Diaminopimelate decarboxylase (DAPDC, EC 4.1.1.20) catalyzes the conversion of diaminopimelate into lysine (Lys), which is the last step in Lys biosynthetic pathway. The genes for DAPDC have been reported in many bacteria, and more recently in Arabidopsis. Here we report characterization of a gene for DAPDC from rice (OsDAPDC). Sequence analysis of a cDNA clone revealed a full-length open reading frame for OsDAPDC that encoded 490 amino acids, approximately 53.2 kDa protein. The OsDAPDC protein contains a consensus binding site for pyridoxal-5'-phosphate as a cofactor and has a sequence at the amino terminus that resembles a transit peptide for localization to plastids, similar to that of Arabidopsis. Single gene encoding DAPDC was found in chromosome II in rice. The predicted amino acid sequence of OsDAPDC is highly homologous to that of the enzymes for DAPDC encoded by lysA of many bacteria. Expression of OsDAPDC in lysA mutants of Escherichia coli shows that the gene is able to functionally complement the mutants. These results suggest that OsDAPDC encodes a protein for diaminopimelate decarboxylase in rice.

• Applied Biological Chemistry
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• v.21 no.3
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• pp.137-143
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• 1978

Xanthine oxidase from bovine thyroid glands was found to contain FAD, molybdenum and iron in a ratio 1:0. 36:1. 6. The molecular weight of the thyroid enzyme was similar to that of the milk enzyme when estimated by gel filtration and polyacrylamide gel electrophoresis. The optimum pH for the enzyme activity was 7.8. The pH of the isoelectric point was determined to be 6.2 by electrofocusing. Sodium dodecyl sulfatepolyacrylamide gel electrophoresis experiment indicated that the enzyme was dissociated into subunits and that the molecular weight for the smallest subunit was 65,000 daltons. Absorption spectra were dissimilar between milk and thyroid xanthine oxidase.

• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.914-920
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• 2011

Vibrio cholerae utilizes mannitol through an operon of the phosphoenolpyruvate-dependent phosphotransferase (PTS) type. A gene, mtlD, encoding mannitol-1-phosphate dehydrogenase was identified within the 3.9 kb mannitol operon of V. cholerae. The mtlD gene was cloned from V. cholerae O395, and the recombinant enzyme was functionally expressed in E. coli as a $6{\times}$His-tagged protein and purified to homogeneity. The recombinant protein is a monomer with a molecular mass of 42.35 kDa. The purified recombinant MtlD reduced fructose 6-phosphate (F6P) using NADH as a cofactor with a $K_m$ of $1.54{\pm}0.1$ mM and $V_{max}$ of $320.8{\pm}7.81\;{\mu}mol$/min/mg protein. The pH and temperature optima for F6P reduction were determined to be 7.5 and $37^{\circ}C$, respectively. Using quantitative real-time PCR analysis, mtlD was found to be constitutively expressed in V. cholerae, but the expression was up-regulated when grown in the presence of mannitol. The MtlD expression levels were not significantly different between V. cholerae O1 and non-O1 strains.

• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.144-148
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• 2013

Lycopene cyclase converts lycopene to ${\beta}$-carotene by catalyzing the formation of two beta-rings at each end of the linear carotene structure. This reaction takes place as a two-step reaction in which both sides of of the lycopene molecule are cyclized into ${\beta}$-carotene rings via the monocyclic ${\gamma}$-carotene as an intermediate. The crtY gene coding for lycopene cyclase from Paracoccus haeundaensis consists of 1,158 base pairs encoding 386 amino acids residues. An expression plasmid containing the crtY gene (pET44a-CrtY) was constructed and expressed in Escherichia coli, and produced a recombinant protein of approximately 43 kDa, corresponding to the molecular mass of lycopene cyclase. The expressed protein was purified to homogeneity by His-tag affinity chromatography and showed enzymatic activity corresponding to lycopene cyclase. We also determined the lycopene substrate specificity and NADPH cofactor requirements of the purified protein. The $K_m$ values for lycopene and NADPH were 3.5 ${\mu}M$ and 2 mM, respectively. The results obtained from this study will provide a wider base of knowledge on the enzyme characterization of lycopene cyclase at the molecular level.

• Journal of Microbiology and Biotechnology
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• v.28 no.6
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• pp.909-916
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• 2018

Previously, a cytosolic trehalase (TreH) from the hyperthermophilic archaeon Sulfolobus acidocaldarius was reported; however, the gene responsible for the trehalase activity was not identified. Two genes, saci_1816 and saci_1250, that encode the glycoside hydrolase family 15 type glucoamylase-like proteins in S. acidocaldarius were targeted and expressed in Escherichia coli, and their abilities to hydrolyze trehalose were examined. Recombinant Saci_1816 hydrolyzed trehalose exclusively without any help from a cofactor. The mass spectrometric analysis of partially purified native TreH also confirmed that Saci_1816 was involved in proteins exhibiting trehalase activity. Optimal trehalose hydrolysis activity of the recombinant Saci_1816 was observed at pH 4.0 and $60^{\circ}C$. The pH dependence of the recombinant enzyme was similar to that of the native enzyme, but its optimal temperature was $20-25^{\circ}C$ lower, and its thermostability was also slightly reduced. From the biochemical and structural results, Saci_1816 was identified as a trehalase responsible for trehalose degradation in S. acidocaldarius. Identification of the treH gene confirms that the degradation of trehalose in Sulfolobus species occurs via the TreH pathway.

• Archives of Pharmacal Research
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• v.27 no.6
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• pp.619-623
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• 2004

Tissue factor (TF, tissue thromboplastin) is a membrane bound glycoprotein, which acceler-ates the blood clotting, activating both the intrinsic and the extrinsic pathways to serve as a cofactor for activated factor VII (Vila). The TF-factor Vila complex (TF/VIIa) proteolytically activates factors IX and X, which leads to the generation of thrombin and fibrin clots. In order to isolate TF inhibitors, by means of a bioassay-directed chromatographic separation technique, from the leaves of Eriobotrya japonica Lindley (Rosaceae), a known sesquiterpene glycoside (2) and ferulic acid (3) were isolated as inhibitors that were evaluated using a single-clotting assay method for determining TF activity. Another sesquiterpene glycoside (1) was also isolated but was inactive in the assay system. Compound 3 was yielded by alkaline hydrolysis of compound 2. The structures of compounds 1, 2, and 3 were identified by means of spectral analysis as $3-O-{\alph}-L-rhamnopyranosyl-(1{\rightarrow}4)-a-L-rhamnopyranosyl-(1{\rightarrow}2)-[{\alph}-L-rhamnopyrano-syl-(1{\rightarrow}6)]-{\beta}-D-glucopyranosyl nerolidol$ (1), $3-O-{\alph}-L-rhamnopyranosyl-(1{\rightarrow}4)-{\alph}-L-rhamnopyr-anosyl-(1{\rightarrow}2)-[{\alph}-L-(4-trans-feruloyl)-rhamnopyranosyl-(1{\rightarrow}6)]-{\beta}-D-glucopyranosyl$ nerolidol (2) and ferulic acid (3), respectively. Compounds 2 and 3 inhibited 50% of the TF activity at con-centrations of 2 and $369{\;}\mu\textrm{m}/TF$ units, respectively.

• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1799-1804
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• 2003

Acetolatate synthase(ALS) catalyzes the first common step in the biosynthesis of valine, leucine, isoleucine in plants and microorganisms. ALS is the target of several classes of herbicides, including the sulfonylureas, the imidazolinones, and the triazolopyrimidines. To elucidate the roles of arginine residues in tobacco ALS, chemical modification and site-directed mutagenesis were performed. Recombinant tobacco ALS was expressed in E. coli and purified to homogeneity. The ALS was inactivated by arginine specific reagents, phenylglyoxal and 2,3-butanedione. The rate of inactivation was a function of the concentration of modifier. The inactivation by butanedione was enhanced by borate, and the inactivation was reversible on removal of excess butanedione and borate. The substrate pyruvate and competitive inhibitors fluoropyruvate and phenylpyruvate protected the enzyme against inactivation by both modifiers. The mutation of well-conserved Arg198 of the ALS by Gln abolished the enzymatic activity as well as the binding affinity for cofactor FAD. However, the mutation of R198K did not affect significantly the binding of FAD to the enzyme. Taken together, the results imply that Arg198 is essential for the catalytic activity of the ALS and involved in the binding of FAD, and that the positive charge of the Arg is crucial for the interaction with negatively charged FAD.

• Korean Journal of Microbiology
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• v.33 no.1
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• pp.43-48
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• 1997

여러가지 난분해성 물질에 대한 생분해능을 지닌 백색부후균에 의한 매립지 침출수의 탈색을 조사하였다. 국내에서 분리한 Coriolus versicolor KR-11W와 Irpex lacteus KR-39W가 이제까지 주로 연구되어 온 Phanerochaete chrysosporium보다 높은 탈색능을 나타내었는데 I. lacteus KR-39W는 산소공급시 10%의 침출수가 함유된 YMG 배지의 진탕배양에서 85%의 색도제거율을 나타내었으며 최소배지에서도 80%의 탈색율을 보였다. P. chrysosporium에 의한 리그닌 분해능 및 분해효소 생성 보고들과 달리 진탕배양이 정치배양보다 탈색능이 높았으며 산소공급은 색도제거에 증가효과가 있었다. 균체 접종량(10-30%)과 온도(25,37.deg. C)는 탈색에 큰 차이를 보이지 않았으나 탄소원과 질소원의 농도는 상당한 영향을 나타내었다. 리그닌 분해효소군의 여러 가지 inducer와 cofactor를 C. versicolor KR-11W 배양에 첨가한 결과 많은 경우 균접종 대조군보다 2배 이상의 탈색율과 lignin peroxidase 활성의 증가를 보였으며 FeS $O_{5}$ 첨가시에는 최대 2.9배의 증가를 나타내었다. 탈색에 관여하는 효소군은 접종물에 이미 어느 정도 존재할 수 있으며 배지 및 배양조건에 따라 그 생성이 변화할 수 있으므로 이런 조건들을 잘 맞출 경우 보다 높은 탈색능이 기대된다.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2984-2988
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• 2009

A gene (PH0311) encoding a hypothetical protein from the genome sequence data of the hyperthermophilic archaeon Pyrococcus horikoshii OT3 was cloned and over-expressed in Escherichia coli. The purified recombinant protein was found to possess FAD-dependent NADH oxidase activity, although it lacked sequence homology to any other known general NADH oxidase family. The product of the PH0311 gene was thus designated PhNOX (NADH oxidase from Pyrococcus horikoshii), with an estimated molecular weight of 84 kDa by gel filtration and 22 kDa by SDS-PAGE, indicating it to be a homotetramer of 22 kDa subunits. PhNOX catalyzed the oxidation of reduced ${\beta}$-NADH with subsequent formation of $H_2O_2$ in the presence of FAD as a cofactor, but not ${\alpha}$-NADH, ${\alpha}$-NADPH, or ${\beta}$-NADPH. PhNOX showed high affinity for ${\beta}$-NADH with a Km value of 3.70 ${\mu}$M and exhibited optimum activity at pH 8.0 and 95$^{\circ}C$ as it is highly stable against high temperature.

• BMB Reports
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• v.41 no.11
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• pp.790-795
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• 2008

An inducible lysine 6-dehydrogenase (Lys 6-DH), which catalyzes the oxidative deamination of the 6-amino group of L-lysine in the presence of $NAD^+$, was purified to homogeneity from Achromobacter denitrificans, yielding a homodimeric protein of 80 kDa. The enzyme was specific for the substrate L-lysine and $NAD^+$ served as a cofactor. The dimeric enzyme associated into a hexamer in the presence of 10 mM L-lysine. The $K_m$ values for L-lysine and $NAD^+$ were 5.0 and 0.09 mM, respectively. The lys 6-dh gene was cloned and overexpressed in E. coli. The open reading frame was 1,107 nucleotides long and encoded a peptide containing 368 amino acids with 39,355 Da. The recombinant enzyme was purified to homogeneity and characterized. Enzyme activities and kinetic properties of the recombinant enzyme were almost the same as those of the endogenous enzyme obtained from A. denitrificans. Crystals of the enzyme were obtained using the hanging drop method.