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1.
Noriharu Umetsu Jun Kaji Keiko Aoyama Kinjiro Tamari 《Bioscience, biotechnology, and biochemistry》2013,77(10):1867-1874
The occurence of tenuazonic acid (T.A.), which had been isolated from the culture broth of blast fungus, in blast-diseased rice plants was surveyed to ascertain whether or not this substance is one of the vivotoxins. T.A. was detected in four of six samples of blast-diseased rice plants, two of which had relatively high T.A. contents; 379 and 91 mg per kg of the samples (dry weight).Besides T.A., coumarin, o-coumaric acid and piricularin were also isolated from blast-diseased rice plants. The molecular formula of the last substance, which was tentatively presented in a previous paper, was corrected to C18H30N2O5 from the results of high resolution mass spectrometry. 相似文献
2.
Synthetic substance P stimulated adenylate cyclase activity in particulate preparations from rat and human brain.The concentration of substance P for half maximal stimulation in rat brain was 1.8 · 10−7 M.The stimulatory effect of substance P on the rat brain adenylate cyclase activity was 88% compared with 48% by noradrenalin, 163% by prostaglandin E1 and 184% by prostaglandin E2.Both the basal and substance P-stimulated adenylate cyclase activity in rat brain were inhibited by concentration of Ca2+ above 10−6 M.The chelating agent ethyleneglycol-bis-(β-aminoethylether)-N,N′-tetraacetic acid at a concentration of 0.1 mM reduced the basal adenylate cyclase activity by 64% and eliminated the substance P-stimulated activity.The inhibition by ethyleneglycol-bis-(β-aminoethylether)-N,N′-tetraacetic acid was completely reversed by increasing concentrations of Ca2+. 相似文献
3.
4.
《Bioscience, biotechnology, and biochemistry》2013,77(5):866-873
Four major molecular species of β-conglycinin, α3, α2β, αβ2, and β3, were isolated and purified from seeds of an α' subunit-deficient strain of soybeans (Glycine max). All components were found to be homogeneous by high pressure liquid chromatography, SDS-polyacrylamide gel electrophoresis, and amino acid and amino terminal sequence analyses. The amino acid compositions of the α3 and β3 components agreed fairly well with the compositions deduced from the cDNA sequences, and all of the components were highly glycosylated. The α3 and β3 components were compared regarding their secondary structures. The secondary structure of the α3 component deduced from CD measurements showed a higher α-helix content than that of the β3 component. The β3 component was crystallized by decreasing the ionic strength from 0.5 to 0.14 in phosphate buffer, pH 7.3, and the crystals grew to a size (1.0 mm × 0.2 mm × 0.2 mm) suitable for X-ray crystallographic analysis. A preliminary X-ray analysis showed that the crystal belonged to an orthorhombic crystal system having the space group P212121 and unit cell dimensions of a = 185.1 Å, b = 107.9 Å, and c = 97.6 Å. 相似文献
5.
Karel Pomeisl Květoslava Horská Radek Pohl Jiří Blažek Marcela Krečmerová 《Nucleosides, nucleotides & nucleic acids》2013,32(3):159-171
A series of new monophosphates of 1-[2-(phosphonomethoxy)alkyl]thymines, such as PMPTp, 3-MeO-PMPTp, HPMPTp, and FPMPTp, were synthesized and tested for their ability to inhibit human thymidine phosphorylase. Kinetic measurements of enzyme activity were performed using thymidine and inorganic phosphate as the substrates. The data show that some monophosphates provide a considerable increase of the multisubstrate inhibitory effect. The highest inhibitory potency was found with (R)-FPMPTp 4c (K i dT = 4.09 ± 0.47 μM, K i(Pi) = 2.13 ± 0.29 μM) and (R) 3-MeO-PMPTp 4d (K i dT = 5.78 ± 0.71 μM, K i(Pi) = 2.71 ± 0.37 μM). 相似文献
6.
Aminoacyl-tRNA synthetase and tRNA were isolated from the chrysomonad Ochromonas danica. The mutual effect of methionine and ethionine, and the effect of other amino acids on methionyl- and ethionyl-tRNA formation, were tested in an in vitro system. The tRNAMet had a similar accepting capacity for either methionine or ethionine. Ethionine and methionine, but none of the other amino acids tested, competed for the same aminoacyl-tRNA synthetase. The Km of methionine was 0.88 × 10–5 M, and that of ethionine 5 × 10–4 M. Ethionine inhibited methionine binding; Ki 3.4 × 10–4 M. The respective values in a similar system isolated from E. coli were 2.2 × 10–5, 1.95 × 10–3, and 1.95 × 10–3. 相似文献
7.
Yoshio Furusawa Yuichiro Kurosawa Isso Chuman 《Bioscience, biotechnology, and biochemistry》2013,77(6):1157-1164
A highly purified trypsin inhibitor was obtained from the oriental plant Hakuhenzu bean (Dolichos lablab) by column chromatography on DEAE-Sephadex and gel-filtration on Sephadex G–75. The purified Hakuhenzu bean trypsin inhibitor (HTI) was obtained as a chemically homogeneous protein, and was stable to heat and to enzymes such as pepsin. It shows no obvious maximum at 280 nm in the ultraviolet absorption spectrum, and it contains more than 20% carbohydrate as galactose and 10% hexosamine as glucosamine. The molecular weight of this inhibitor was determined to be approximately 9,500 by gel-filtration. The protein contained 59 residures of amino acids; Lys3, His4, Arg1, Asp8, Thr3, Ser9, Glu6, Pro5, Gly1, Ala3, l/2Cys10, Val1, Ile1, Leu2, Tyr1, Phe1, from which a molecular weight of 6,400 is obtained. No methionine and tryptophan were found in the amino acid composition of the inhibitor. This inhibitor showed inhibitory activity against α-chymotrypsin in addition to trypsin. 相似文献
8.
Kiroyasu Watanabe Akio Ide Yoshio Ogawa 《Bioscience, biotechnology, and biochemistry》2013,77(4):269-271
A new substance, molecular formula C8H10O2, was isolated from the unripe fruits of Citrullus colocynthis, SCHRAD. Judging from the results of infrared absorption spectra, properties of the derivatives and the oxidative product of methyl derivative, this substance was pressumed to be p-hydroxybenzyl methyl ether and this assumption was proved beyond doubt by its direct comparison with an authentic synthesized sample. 相似文献
9.
Baumler DJ Hung KF Jeong KC Kaspar CW 《Extremophiles : life under extreme conditions》2007,11(6):841-851
Acidophiles are typically isolated from sulfate-rich ecological niches yet the role of sulfur metabolism in their growth and
survival is poorly defined. Studies of heterotrophically grown “Ferroplasma acidarmanus” showed that its growth requires a minimum of 100 mM of a sulfate-containing salt. Headspace gas analyses by GC/MS determined
that the volatile sulfur compound emitted by active “F. acidarmanus” cultures is methanethiol. In “F. acidarmanus” cultures grown either heterotrophically or chemolithotrophically, methanethiol was produced constitutively. Radiotracer
studies with 35S-labeled methionine, cysteine, and sulfate showed that all three were used in methanethiol production. Additionally, 3H-labeled methionine was incorporated into methanethiol and was probably used as a methyl-group donor. Methanethiol production
in whole cell lysates supplied with SO32− indicated that NADPH-dependant sulfite reductase and methyltransferase activities were present. Cell lysates also contained
enzymatic activity for methionine-γ-lyase that cleaved the side chain of either methionine to form methanethiol or cysteine
to produce H2S. Since methanethiol was detected from the degradation of cysteine, it is likely that sulfide was methylated by a thiol methyltransferase.
Collectively, these data demonstrate that “F. acidarmanus” produces methanethiol through the metabolism of methionine, cysteine, or sulfate. This is the first report of a methanethiol-producing
acidophile, thus identifying a new contributor to the global sulfur cycle. 相似文献
10.
Purification and Characterization of β-N-Acetylhexosaminidase from the Liver Prawn,Penaeus japonicus
《Bioscience, biotechnology, and biochemistry》2013,77(2):194-199
β-N-Acetvlhexosaminidase (EC 3.2.1.52) was purified from the liver of a prawn, Penaeus japonicus, by ammonium sulfate fractionation and chromatography with Sephadex G-100, hydroxylapatite, DEAE-Cellulofine, and Cellulofine GCL-2000-m. The purified enzyme showed a single band keeping the potential activity on both native PAGE and SDS–PAGE. The apparent molecular weight was 64,000 and 110,000 by SDS–PAGE and gel filtration, respectively. The pI was less than 3.2 by chromatofocusing. The aminoterminal amino acid sequence was NH2-Thr-Leu-Pro-Pro-Pro-Trp-Gly-Trp-Ala-?-Asp-Gln-Gly-VaI-?-Val-Lys-Gly-Glu-Pro-. The optimum pH and temperature were 5.0 to 5.5 and 50°C, respectively. The enzyme was stable from pH 4 to 11, and below 55°C. It was 39% inhibited by 10mM HgCl2.Steady-state kinetic analysis was done with the purified enzyme using N-acetylchitooligosaccharides (GlcNAcn, n = 2 to 6) and p-nitrophenyl N-acetylchitooligosaccharides (pNp-β-GlcNAcn, n= 1 to 3) as the substrates. The enzyme hydrolyzed all of these substrates to release monomeric GlcNAc from the non-reducing end of the substrate. The parameters of Km and kcat at 25°C and pH 5.5 were 0.137 mM and 598s–1 for pNp-β-GlcNAc, 0.117 mM and 298s–1 for GlcNAc2, 0.055 mM and 96.4s–1 for GlcNAc3, 0.044 mM and 30.1 s–1 for GlcNAc4, 0.045 mM and 14.7 s–1 for GlcNAc5, and 0.047 mM and 8.3 s–1 for GlcNAc6, respectively. These results suggest that this β-N-acetylhexosaminidase is an exo-type hydrolytic enzyme involved in chitin degradation, and prefers the shorter substrates. 相似文献
11.
Yuzuru Mikami Sen Feng Yu Katsukiyo Yazawa Kazutaka Fukushima Akio Maeda Jun Uno Kiyoshi Terao Naoki Saito Akinori Kubo Ken -ichiro Suzuki 《Mycopathologia》1990,112(2):113-118
During our studies on toxic substances from clinically isolated Nocarida, a new isolate identified as Nocardia otitidiscaviarum from cutaneous nocardiosis was found to produce a toxic substance called HS-6 that had strong in vitro as well as in vivo toxicity. The mouse intraperitoneal LD50 value was 1.25 mg/kg and the ED50 value for L1210 cultured cells was 0.3 ng/ml. The structure of HS-6 was determined and found to belong to the 16-membered macrocyclic group with a molecular formula of C43H68O12. HS-6 also showed activity against pathogenic fungi such as Cryptococcus neoformans. 相似文献
12.
Heiichi Sakai Rimpei Mori Kei Arima 《Bioscience, biotechnology, and biochemistry》2013,77(10):660-678
The production and isolation of a new toxic substance, Teleocidin, and its biological properties were previously reported1,2). Thereafter it has been found that an other strain of Streptomyces produced such specific toxic substance as Teleocidin in its cultured mycellium. Comparative tests of these two purified crystalline powders showed the new toxic substance resembles Teleocidin closely though differs in certain chemical properties. Therefore, the original Teleocidin is designated Teleocidin A, whereas that produced by a new strain of Streptomyces is named Teleocidin B, which had been tentatively called as the SK-toxic substance.From the results of the chemical studies of Teleocidin B and its hydrogenated derivative, which was easily obtained as a crystalline form by the catalytic hydrogenation of Teleocidin B with Adam’s catalyst, molecular formula, C28H39~41N3O2 was postulated for Teleocidin B.It was also recognized that an alcoholic hydroxyl, a lactam ring and a heterocyclic ring like indole or pyrrole structure existed as the functional groups of Teleocidin B. 相似文献
13.
Isotopic and genetic analyses of a mass grave in central California: Implications for precontact hunter‐gatherer warfare
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Jelmer W. Eerkens Traci Carlson Ripan S. Malhi Jennifer Blake Eric J. Bartelink Gry H. Barfod Alan Estes Ramona Garibay Justin Glessner Alexandra M. Greenwald Kari Lentz Hongjie Li Charla K. Marshall 《American journal of physical anthropology》2016,159(1):116-125
14.
The spectral changes caused by binding soft ligands to the cytochrome c iron and their correlation to ligand affinities support the hypothesis that the iron—methionine sulfur bond of this heme protein is enhanced by delocalization of the metal l2, electrons into the empty 3d orbitals of the ligand atom. These findings also explain the unique spectrum of cytochrome c in the far red. 相似文献
15.
P.D. East T.D. Sutherland S.C. Trowell A.J. Herlt R.W. Rickards 《Archives of insect biochemistry and physiology》1997,34(2):239-253
The major radiolabelled product released from ring gland and brain-ring gland complexes of third instar larval and pre-pupal stages of the sheep blowfly Lucilia cuprina upon incubation with L-[methyl-3H]methionine corresponded to one diastereomer of juvenile hormone III bisepoxide (JHB3). Endocrine glands incubated with the juvenile hormone precursor 2E,6E-farnesoic acid released increased quantities of JHB3, together with significant amounts of juvenile hormone III but not the isomeric methyl 2E-6,7-epoxyfarnesoate. Synthesis of JHB3 was developmentally and neurally regulated. Ring glands and brain-ring gland complexes from third instar larvae released more JHB3 than comparable preparations from pre-pupae, while isolated corpus allatum segments of the gland were more active than intact brain-gland complexes. These results reinforce the emerging status of JHB3 as the characteristic juvenile hormone of dipteran insects. Arch. Insect Biochem. Physiol. 34:239–253, 1997. © 1997 Wiley-Liss, Inc. 相似文献
16.
Sarela García‐Santamarina Susanna Boronat José Ayté Elena Hidalgo 《Molecular microbiology》2013,90(5):1113-1124
Amino acid methionine can suffer reversible oxidation to sulphoxide and further irreversible over‐oxidation to methionine sulphone. As part of the cellular antioxidant scavenging activities are the methionine sulphoxide reductases (Msrs), with a reported role in methionine sulphoxide reduction, both free and in proteins. Three families of Msrs have been described, but the fission yeast genome only includes one representative for two of these families: MsrA/Mxr1 and MsrB/Mxr2. We have investigated their role in methionine reduction and H2O2 sensitivity. We show here that MsrA/Mxr1 is able to reduce free oxidized methionine. Cells lacking each one of the genes are not significantly sensitive to different types of oxidative stresses, neither display altered life span. However, only when deletion of msrA/mxr1 is combined with deletion of met6, which confers methionine auxotrophy, the survival upon H2O2 stress decreases by 100‐fold. In fact, cells lacking only Met6, and which therefore require addition of methionine to the growth media, are extremely sensitive to H2O2 stress. These and other evidences suggest that oxidation of free methionine is a primary target of peroxide toxicity in cells devoid of methionine biosynthetic capacity, and that an important role of Msrs is to recycle this oxidized free amino acid. 相似文献
17.
Modrak-Wójcik A Kirilenko A Shugar D Kierdaszuk B 《European biophysics journal : EBJ》2008,37(2):153-164
Kinetics of the reactions of purine nucleoside phosphorylases (PNP) from E. coli (PNP-I, the product of the deoD gene) and human erythrocytes with their natural substrates guanosine (Guo), inosine (Ino), a substrate analogue N(7)-methylguanosine
(m7Guo), and orthophosphate (Pi, natural cosubstrate) and its thiophosphate analogue (SPi), found to be a weak cosubstrate, have been studied in the pH range 5–8. In this pH range Guo and Ino exist predominantly
in the neutral forms (pKa 9.2 and 8.8); m7Guo consists of an equilibrium mixture of the cationic and zwitterionic forms (pKa 7.0); and Pi and SPi exhibit equilibria between monoanionic and dianionic forms (pKa 6.7 and 5.4, respectively). The phosphorolysis of m7Guo (at saturated concentration) with both enzymes exhibits Michaelis kinetics with SPi, independently of pH. With Pi, the human enzyme shows Michaelis kinetics only at pH ∼5. However, in the pH range 5–8 for the bacterial enzyme, and 6–8
for the human enzyme, enzyme kinetics with Pi are best described by a model with high- and low-affinity states of the enzymes, denoted as enzyme-substrate complexes with
one or two active sites occupied by Pi, characterized by two sets of enzyme-substrate dissociation constants (apparent Michaelis constants, K
m1 and K
m2) and apparent maximal velocities (V
max1 and V
max2). Their values, obtained from non-linear least-squares fittings of the Adair equation, were typical for negative cooperativity
of both substrate binding (K
m1 < K
m2) and enzyme kinetics (V
max1/K
m1 > V
max2/K
m2). Comparison of the pH-dependence of the substrate properties of Pi versus SPi points to both monoanionic and dianionic forms of Pi as substrates, with a marked preference for the dianionic species in the pH range 5–8, where the population of the Pi dianion varies from 2 to 95%, reflected by enzyme efficiency three orders of magnitude higher at pH 8 than that at pH 5.
This is accompanied by an increase in negative cooperativity, characterized by a decrease in the Hill coefficient from n
H ∼1 to n
H ∼0.7 for Guo with the human enzyme, and to n
H ∼0.7 and 0.5 for m7Guo with the E. coli and human enzymes, respectively. Possible mechanisms of cooperativity are proposed. Attention is drawn to the substrate properties
of SPi in relation to its structure. 相似文献
18.
Repetition of an investigation of the petrol extracts of Rhodomyrtus tomentosa has led to the isolation of two new triterpenoids, R4 from the leaves and R5 from the stems besides R1, R2, R3 and the other known compounds already reported. R1 and R4 were proved to be 21α-hop-22(29)en-3β,30-diol and 3β-hydroxy-21α-hop-22(29)-en-30-al respectively, and R2, R3 and R5 are 3β-acetoxy-11α,12α-epoxyoleanan-28,13β-olide, 3β-acetoxy-12α-hydroxyoleanan-28, 13β-olide and 3β-acetoxy-12-oxo-oleanan-28,13β- olide respectively. The ethanol extract of the leaves contained betulinic, ursolic and aliphitolic acids and that of the stems betulonic, betulinic and oleanolic acids. 相似文献
19.
It was found that the precursor of the sunstruck flavor was formed in the course of maturing sake cake. A large quantity of yeasts in the sake cake was autolysed and VB2 was evolved. Like the sunstruck flavor of milk reported by Patton et al. it is thought that, VB2, a photochemical sensitization substance caused methionine to react photochemically and to evolve the sunstruck flavor 3-(methylthio)-propanal (methional). Organoleptically, vinegar with added methional an vinegar which had evolved the sunstruck flavor had the same odor. 相似文献
20.
Uptake of sulphate,taurine, cysteine and methionine by symbiotic and free-living dinoflagellates 总被引:1,自引:0,他引:1
Sulphate uptake by Amphidinium carterae, Amphidinium klebsii and Gymnodinium microadriaticum grown on artificial seawater medium with sulphate, cysteine, methionine or taurine as sulphur source occurred via an active transport system which conformed to Michaelis-Menten type saturation kinetics. Values for K
m ranged from 0.18–2.13 mM and V
max ranged from 0.2–24.2 nmol · 105 cells–1 · h–1. K
m for symbiotic G. microadriaticum was 0.48 mM and V
max was 0.2 nmol · 105 cells–1 · h–1. Sulphate uptake was slightly inhibited by chromate and selenate, but not by tungstate, molybdate, sulphite or thiosulphate. Cysteine and methionine (0.1 mM), but not taurine, inhibited sulphate uptake by symbiotic G. microadriaticum, but not by the two species of Amphidinium. Uptake was inhibited 45–97% under both light and dark conditions by carbonylcyanide 3-chlorophenylhydrazone (CCCP); under dark conditions sulphate uptake was 40–60% of that observed under light conditions and was little affected by 3-(3,4-dichlorophenyl) 1,1-dimethylurea (DCMU).The uptake of taurine, cysteine and methionine by A. carterae, A. klebsii, cultured and symbiotic G. microadriaticum conformed to Michaelis-Menten type saturation kinetics. K
m values of taurine uptake ranged from 1.9–10 mM; for cysteine uptake from 0.6–3.2 mM and methionine from 0.001–0.021 mM. Cysteine induced a taurine uptake system with a K
m of 0.3–0.7 mM. Cysteine and methionine uptake by all organisms was largely unaffected by darkness or by DCMU in light or darkness. CCCP significantly inhibited uptake of these amino acids. Thus energy for cysteine and methionine uptake was supplied mainly by respiration. Taurine uptake by A. carterae was independent of light but was inhibited by CCCP, whereas uptake by A. klebsii and symbiotic G. microadriaticum was partially dependent on photosynthetic energy. Taurine uptake by cultured G. microadriaticum was more dependent on photosynthetic energy and was more sensitive to CCCP. Cysteine inhibited uptake of methionine and taurine by cultured and symbiotic G. microadriaticum to a greater extent than in the Amphidinium species. Methionine did not greatly affect taurine uptake, but did inhibit cysteine uptake. Taurine did not affect the uptake of cysteine or methionine. 相似文献