Go toArchive
Browse byFacets
Bookbag ( 0 )
'Inhibitor' in keywords
Results  28 Items
Sorted by   
Section
Publication Year
1998 (1)
1997 (1)
1996 (1)
1992 (1)
1986 (1)
1985 (2)
1984 (2)
1983 (4)
1981 (5)
1980 (2)
1979 (5)
1977 (1)
1976 (1)
1974 (1)
1Author    J. Markopoulos, D. JannakoudakisRequires cookie*
 Title    Über die inhibierende Wirkung grenzflächenaktiver Stoffe auf die polarographische Reduktion von Cd 2+ -, Zn 2+ -und Co 2+ -Ionen in wasser-methanolischen und methanolischen Lösungen On the Inhibition Effect of Surfactants on the Polarographic Reduction of Cd 2+ , Zn 2+ and Co 2+ Ions in Aqueous Methanolic and Methanolic Solutions  
 Abstract    The inhibition effect of tri-n-octylphosphine oxide (TOPO), triphenylarsine oxide (TAsO), triphenylphosphine oxide (TPO), triphenylarsine (TPAs) and triphenylphosphine (TPP) on the polarographic reduction of Cd 2+ , Zn 2+ and Co 2+ ions in aqueous methanolic and methanolic solutions has been studied. 
  Reference    Z. Naturforsch. 36b, 1089—1092 (1981); eingegangen am 18. Mai 1981 
  Published    1981 
  Keywords    Polarography, Inhibitors, Electroreduction, Triphenylarsine Oxide 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-1089.pdf 
 Identifier    ZNB-1981-36b-1089 
 Volume    36 
2Author    AngelM. RelimpioRequires cookie*
 Title    Structure and Anticholinesterase Activity of Series of Ethyl Substituted Phenyl Methylphosphonates  
 Abstract    Thirty derivates from substituted-phenyl-ethyl methylphosphonates have been synthesized and their inhibiting power of acetyl-cholinesterase have been examined in vitro and in vivo. The cor­ relation between inhibition of the enzyme and electrophylic power of the substituent of the phenyl group was excellent, but when this group contains two substituents, steric factors appear to operate. The activity of these compounds has been demonstrated to be higher than their phosphate analogs. 
  Reference    (Z. Naturforsch. 32c, 760 [1977]; received June 13 1977) 
  Published    1977 
  Keywords    Cholinesterase, Methylphosphonates, Inhibitors, Biological Activity 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/32/ZNC-1977-32c-0760.pdf 
 Identifier    ZNC-1977-32c-0760 
 Volume    32 
3Author    ArminH. Ildebrandt, Rudolf Mengel, HelmutW. SauerRequires cookie*
 Title    Characterization of an Endogenous Transcription Inhibitor from Physarum polycephalum  
 Abstract    A substance has been purified from isolated nuclei of Physarum polycephalum by equilibrium and velocity gradient centrifugations, ion exchange chromatography and gel filtration which has a high molecular weight, can be labeled in vivo with 32P, is heat stable and resistant to amylases, proteases, nucleases and phosphodiesterase but is sensitive to phosphatases or hydrolysis. This material consists of phospate and glycerol. It selectively inhibits in vitro transcription of RNA polymerases, predominantly the homologous enzyme A by binding to the enzyme. In the presence of this inhibitor of transcription a stable RNA polymerase-template complex cannot be formed. Binding to and inactivation of RNA polymerase is reversible at high ionic strength. 
  Reference    Z. Naturforsch. 34c, 76 (1979); received July 3/ November 21 1978 
  Published    1979 
  Keywords    RNA polymerases, Inhibitor, Glycerophosphate, Physarum 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0076.pdf 
 Identifier    ZNC-1979-34c-0076 
 Volume    34 
4Author    W. Alter OettmeierRequires cookie*
 Title    Quantitative Structure Activity Relationship of Diphenylamines as Inhibitors of Photosynthetic Electron Transport and Photophosphorylation  
 Abstract    A number of 16 substituted diphenylamines have been tested for their inhibitory activity on photosynthetic NADP reduction and photophosphorylation. The most active compounds exhibited p l50 values of 6.0 in photosynthetic electron transport and 6.8 in cyclic photophosphorylation, respectively. The inhibition site in electron flow of the diphenylamines is located between the two photosystems. Necessary for high activity is the substitution of the phenyl moieties by several strongly electron withdrawing substituents. A quantitative structure activity relationship according to a parabolic Hansch approach could be accomplished by using the Hammett electronic parameter as the only variable. 
  Reference    Z. Naturforsch. 34c, 1024—1027 (1979); received May 31 1979 
  Published    1979 
  Keywords    Diphenylamines, Inhibitors, Photosynthetic Electron Transport 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-1024.pdf 
 Identifier    ZNC-1979-34c-1024 
 Volume    34 
5Author    Magdolna Droppa, Sándor Demeter, Zsuzsa Rózsa, G. Ábor HorváthRequires cookie*
 Title    Reinvestigation of the Effects of Disalicylidenepropanediamine (DSPD) and 2-HeptyM-hydroxyquinoline-N-oxide (HQNO) on Photosynthetic Electron Transport  
 Abstract    The effects of disalicylidenepropanediamine (DSPD) and 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO) on photosynthetic electron transport have been reexamined. The results confirm earlier observations that lower concentrations of DSPD (< 100 hm) block electron transport at the levels of ferredoxin and plastocyanin. High concentrations o f DSPD even inhibit electron transport from HaO -> pBQ, suggesting that DSPD has an inhibitory site in PS II as well. Thermoluminescence curves o f DSPD and DCMU treated chloroplasts were very similar, showing that the third inhibitory site o f DSPD is similar to that o f DCMU. Both oxidized and reduced HQNO, (0 .6 -6 hm) blocked electron transport from H20 -* pBQ, H20 -*■ MV/FeCy to a similar extent. The effect of HQNO on thermoluminescence showed that its inhibitory site is probably located before that o f DCMU. At higher concentration (> 6 h m) , the H20 -*■ MV/FeCy reactions were more strongly inhibited by oxidized HQNO than those occuring from H20 -> pBQ, suggesting that a new site o f inhibition must also be considered. The dark decay of the P 700 signal was not influenced by the addition o f oxidized HQNO which shows that the new inhibitory site of HQNO is located between plastoquinone and P 700. The reduced form of HQNO did not inhibit non-cyclic electron transport around PS I. Indeed, at higher concentrations, reduced HQNO even accelerates electron flow from DCIP -» MV and the dark reduction of P 700, thus suggesting that this compound has a "donor-mediator" function in PS I. 
  Reference    Z. Naturforsch. 36c, 109 (1981); received September 8/October 28 1980 
  Published    1981 
  Keywords    Inhibitors, Electron Transport, Chloroplasts, Thermoluminescence 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0109.pdf 
 Identifier    ZNC-1981-36c-0109 
 Volume    36 
6Author    A. Trebst, B. D. Epka, S. M. Ridley, A. F. HawkinsRequires cookie*
 Title    Inhibition of Photosynthetic Electron Transport by Halogenated 4-Hydroxy-pyridines  
 Abstract    Herbicidal halogen substituted 4-hydroxypyridines are inhibitors of photosynthetic electron flow in isolated thylakoid membranes by interfering with the acceptor side of photosystem II. Tetrabromo-4-hydroxypyridine, the most active compound found, has a pl50-value of 7.6 in the inhibition of oxygen evolution in both the reduction of an acceptor of photosystem I and an acceptor of photosystem II. The new inhibitors displace both metribuzin and ioxynil from the membrane. The 4-hydroxypyridines, like ioxynil, have unimpaired inhibitor potency in Tris-treated chloroplasts, whereas the DCMU-type family of herbicides does not. It is suggested that 4-hydroxypyridines are complementary to phenol-type inhibitors, and a common essential element is proposed. The 4-hydroxypyridines do not inhibit photosystem I or non-cyclic electron flow through the cytochrome b/f complex. But they do have a second inhibition site in photosynthetic electron transport since they inhibit ferredoxin-catalyzed cyclic electron flow, indicating an antimycin-like property. A comparison of the in vitro potency of the compounds with the in vivo potency shows no correlation. A major herbicidal mode of action of the group is related to the inhibition of carotenoid synthesis, and access to the chloroplast lamellae in vivo for inhibition of electron transport may be restricted. 
  Reference    Z. Naturforsch. 40c, 391—399 (1985); received February 28 1985 
  Published    1985 
  Keywords    Herbicides, Hydroxypyridines, Inhibitors, Photosynthesis 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0391.pdf 
 Identifier    ZNC-1985-40c-0391 
 Volume    40 
7Author    Dimitrios Jannakoudakis, Elli TheodoridouRequires cookie*
 Title    Über den Einfluß des pH-Wertes auf die polarographische Reduktion der Nitrophenole mit und ohne Zusatz von Campher On the Influence of the pH Value on the Polarographic Reduction of the Nitrophenols in Presence and Absence of Campher  
 Abstract    The Polarographie behavior of the nitrophenols in the pH range 1-13 and the in-fluence of campher on the polarographic curves are studied. The pH dependence of the half wave potentials and the different reduction of the depolarizers in their molecular or anionic form are discussed. 
  Reference    Z. Naturforsch. 35b, 705—708 (1980); eingegangen am 8. Februar 1980 
  Published    1980 
  Keywords    Nitrophenols, Polarography, Half Wave Potential, Inhibitor 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/35/ZNB-1980-35b-0705.pdf 
 Identifier    ZNB-1980-35b-0705 
 Volume    35 
8Author    A. Trebst, E. HarthRequires cookie*
 Title    Herbicidal N-Alkylated-Ureas and Ringclosed N-Acylamides as Inhibitors of Photosystem II  
 Abstract    The inhibitory action of some herbicides on photosynthetic electron flow at photosystem I I in isolated chloroplasts was investigated. Emphasis in the study is on compounds, whose chemical structure seemed to be in disaccordance with the basic structural element, proposed to be required for a photosystem II inhibitor. The effective inhibition of photosynthetic oxygen evolution by N-alkylated urea-, pyrrolidone-and by substituted pyridazine-derivatives without a free NH-group is reported. A revised basic chemical structural element responsible for inhibition is deduced in order to include lactames (ringclosed N-acylamides) with and without hetero atoms. From this new groups of potential inhibitors, like triazolone-, thiadiazolone-and oxadiazolone-derivatives may be conceived. 
  Reference    (Z. Naturforsch. 29c, 232 [1974]; received February 4 1974) 
  Published    1974 
  Keywords    Inhibitor, Herbicides, Photosynthesis, Photosystem II, Chloroplasts 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0232.pdf 
 Identifier    ZNC-1974-29c-0232 
 Volume    29 
9Author    Achim TrebstRequires cookie*
 Title    Artificial Energy Conservation in Bacterial Photosynthetic Electron Transport  
 Abstract    In photosynthesis of chloroplasts and bacterial chromatophores an induced artificial electron flow bypass may restore the inhibition of electron flow and of coupled A T P formation by two possible mechanisms. An artificial transmembrane electron flow bypass will lead to artificial energy conservation, when the redox reaction cycle of the added mediator across the membrane acts as proton pump. In an artificial internal electron floiv bypass an inhibited native energy conservation may be reactivated; here an electron flow bypass induced by the mediator in the inside space restores the native proton translocation. The inhibition and the restoration of electron flow by antimycin, dibromothymoquinone and valinomycin 
  Reference    (Z. Naturforsch. 31c, 152 [1976]; received November 24 1975) 
  Published    1976 
  Keywords    Bacterial Photosynthesis, Adenosine Triphosphate Formation, Inhibitors, Photosynthetic Electron Transport 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0152.pdf 
 Identifier    ZNC-1976-31c-0152 
 Volume    31 
10Author    A. Trebst, S. R. Eim Er, W. Draber, H. J. KnopsRequires cookie*
 Title    The Effect of Analogues of Dibromothymoquinone and of Bromonitrothymol on Photosynthetic Electron Flow  
 Abstract    Alkyl substituted derivatives of halogenated p-benzoquinones, of halogenated /7-nitrophenols, and of 2,4-dinitrophenols were tested in the inhibition of photosynthetic electron flow in chloro­ plasts. The effect of the compounds on photoreductions by photosystem I or II, on a TMPD bypass in NADPH formation and the reversibility of the inhibition by dithiothreitol is used to distin­ guish between an inhibition site before or after plastoquinone function, i. e. between a DBMIB versus a DCMU inhibition pattern. It is shown, that different isopropyl and /-butyl substituted halogenated p-benzoquinones are as effective and specific as DBMIB in the inhibition of plastoquinone function. Alkyl substituted /^-nitrophenols, with an additional halogen-or nitro-group at C-2, are shown to be effective electron flow inhibitors. The new potent nitrophenol derivatives inhibit at the site of DCMU action, nevertheless they do not contain the basic chemical element essential for inhibi­ tion common to DCMU and its many herbicidal analogues. Small changes in the ring-substitution can alter the inhibition pattern from a DCMU typ to a DBMIB typ inhibition. 
  Reference    Z. Naturforsch. 34c, 831 (1979); received June 1 1979 
  Published    1979 
  Keywords    Photosynthesis, Inhibitors, Herbicides, Dibromothymoquinone, Nitrophenols, Chloroplast 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0831.pdf 
 Identifier    ZNC-1979-34c-0831 
 Volume    34 
11Author    Klaus Pfister, CharlesJ. ArntzenRequires cookie*
 Title    The Mode of Action of Photosystem II-Specific Inhibitors in Herbicide-Resistant Weed Biotypes  
 Abstract    This report reviews studies which provide evidence defining the mode of action and site of action of photosystem II (PS II) herbicides; the involvement of the secondary electron carrier on the reducing side of PS II (called B) is indicated as the target site for these compounds. These studies of the action of PS II-inhibitors were perform ed in chloroplasts of various weed species in order to define the mechanism which is responsible for herbicide tolerance at the level of chloroplast mem branes in newly discovered triazine-resistant weed biotypes. M any species of triazine-resistant weed biotypes have been collected in N orth America and Europe. W here data is available, these plants have been found to share the following common fe atu res: a) they were discovered in areas where triazine herbicides had been used repeatedly, b) resistance to the triazines is extrem e; it is not due to a m inor shift in herbicidal response, c) no changes in herbicide uptake, translocation or metabolism — as compared to susceptible bio­ types — can be detected, d) resistance is selective for only certain classes of photosynthetic herbicides, and, e) chloroplasts isolated from triazine-resistant weeds display high preferential resistance to the triazines in assays of photosystem II partial reactions. To focus on the mechanism which regulates preferential herbicide activity, we have characterized susceptible and resistant chloroplasts in the presence and absence of herbicides. Properties of the PS II complex of chloroplasts from several different triazine-resistant weed biotypes share the fol­ lowing tr a its : a) the herbicide binding site (as measured by direct binding of radiolabeled herbicides or by in­ hibition experiments) is modified such that the affinity for triazines is dram atically reduced. b) alterations in response to many PS II-herbicides occur such th at the triazine-resistant chloro­ plasts are very strongly resistant to all sym m etrical triazines, strongly resistant to assymmetrical triazinones, partially resistant to pyridazones and uracils, only slightly resistant to ureas or amides, and increasingly susceptible to nitrophenols, phenols and the herbicide bentazon (all as compared to susceptible chloroplasts), c) there is a change in the reaction kinetics of the electron transport step between the prim ary and secondary electron acceptors (referred to as Q and B), and d) in two examples, specific small changes in a m em brane polypeptide can be detected in the resistant thylakoids. We suggest that certain amino acids or segments of the apoprotein of B (the bound quinone which acts as the secondary electron carrier) are modified or deleted in these chloroplasts. Such a polypeptide change could affect both the redox poising of the Q~/B reaction pair, and the specific binding of herbicides. 
  Reference    Z. Naturforsch. 34c, 996—1009 (1979); received June 29 1979 
  Published    1979 
  Keywords    Herbicide, Resistance, Photosynthesis, Electron Transport, Inhibitors 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0996.pdf 
 Identifier    ZNC-1979-34c-0996 
 Volume    34 
12Author    Toshihisa Ohshima, Gerhart DrewsRequires cookie*
 Title    Isolation and Partial Characterization of the Membrane-Bound NADH Dehydrogenase from the Phototrophic Bacterium Rhodopseudomonas capsulata  
 Abstract    Chem otrophically grown cells of Rhodopseudomonas capsulata contain at least three different pyridine nucleotide dehydrogenases, i) a soluble, found in the supernatant (144000 x g) o f cell free extracts, N AD H-dependent, ii) a mem brane-bound, N AD H -dependent, and iii) a soluble, found in the supernatant N AD PH dependent. i The m em brane-bound N A D H dehydrogenase (E.C. 1.6.99.3) has been solubilized by sodium deoxycholate treatm ent of m em branes and purified 75 fold by column chrom atography on Sephadex G-150 and DEAE cellulose in the presence of sodium cholate. The native enzyme has an apparent molecular mass (M r) o f 97 000, containing polypeptides of Mr of about 15 000. The pH optim um was at 7.5. The enzyme was specific for NADH. The Michaelis constant for NADH and DCIP were 4.0 and 63 hm, respectively. The enzyme was inactivated by FM N, riboflavin and NADH. In contrast, the soluble N ADH-dehydrogenase (i) was activated by FMN. 
  Reference    Z. Naturforsch. 36c, 400 (1981); received February 23/M arch 16 1981 
  Published    1981 
  Keywords    NADH Dehydrogenase, Purification, Localization, Inhibitors, Rhodopseudomonas capsulata 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0400.pdf 
 Identifier    ZNC-1981-36c-0400 
 Volume    36 
13Author    Klaus Pfister, H. Artm, K. Lichtenthaler, G. Ünther Burger, Hans Musso, M.Anuel ZahnRequires cookie*
 Title    The Inhibition of Photosynthetic Light Reactions by Halogenated Naphthoquinones  
 Abstract    Halogenated naphthoquinones act as inhibitors o f photosynthetic electron flow. I50 concentra­ tion for inhibition of methylviologen reduction were found to range between 2 x 10-5 m to 2 x 10-6 M. Comparing their effects on several partial reactions o f electron flow, the inhibition site o f the naphthoquinones was found to be at the reducing site o f PS II. Studies o f fluorescence transients in presence o f halogenated naphthoquinones give further evidence for a site action similar to that o f diuron and different to that of DBMIB. All naphthoquinones act as quenchers o f chlorophyll fluorescence with pure chlorophyll a, and with much higher efficiency in green algae and chloroplasts. It is concluded, that the halogenated naphthoquinones act similar to PS II-inhibitors like diuron, but do not share a common binding site at the PS II-complex. Implications of a possible involvement of phylloquinone K 1 in photosynthetic electron transport are discussed. The synthesis o f 2-chloro-as well as 2-bromo-3-isopropyl-1,4-naphthoquinone is described. 
  Reference    Z. Naturforsch. 36c, 645—655 (1981); received April 271981 
  Published    1981 
  Keywords    Chlorophyll Fluorescence, Electron Transport, Inhibitors, Naphthoquinones, Photosynthesis, Quenchers 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0645.pdf 
 Identifier    ZNC-1981-36c-0645 
 Volume    36 
14Author    Jacek Wierzchowski, David ShugarRequires cookie*
 Title    Sensitive Fluorimetric Assay for Adenosine Deaminase with Formycin as Substrate; and Substrate and Inhibitor Properties of some Pyrazolopyrimidine and Related Analogues  
 Abstract    The nucleoside antibiotic formycin, 7-amino-3-(/?-D-ribofuranosyl)pyrazolo(4,3-d)pyrimidine, a structural analogue of adenosine, is deaminated about 10-fold faster by adenosine deaminase than adenosine itself, and is therefore a superior substrate for both routine assays and kinetic studies with the purified enzyme. The luminescence properties o f formycin have been profited from to develop a fluorimetric assay for adenosine deaminase which is considerably more sensi­ tive than the spectrophotometric procedure widely employed with adenosine as substrate. Exam­ ples are presented of its application to routine assays of adenosine deaminase levels in cellular extracts, as well as to kinetic studies with the purified enzyme, including the properties o f some pyrazolopyrimidine and purine substrates and inhibitors. 
  Reference    Z. Naturforsch. 38c, 67—7 (1983); received August 23 1982 
  Published    1983 
  Keywords    Formycin, Pyrazolopyrimidines, Adenosine Deaminase, Fluorimetric Assay, Inhibitors 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0067.pdf 
 Identifier    ZNC-1983-38c-0067 
 Volume    38 
15Author    Friedrich Jiittner, O. Ttm Ar BogenschützRequires cookie*
 Title    Geranyl Derivatives as Inhibitors o f the Carotenogenesis in Synechococcus PCC 6911 (Cyanobacteria)  
 Abstract    The ability of several geranyl derivatives to inhibit carotenoid synthesis in Synechococcus (Cyanobacteria) was measured using a cyanobacterial bioassay. The inhibitory activity o f differ­ ent molecules varied according to chain length and substituents. Pseudoionone, famesyl acetate, geranyl acetate, geranial and farnesol proved to be the most active derivatives tested. 6-Methylhept-5-en-2-one, farnesyl acetone, linalool and geranyl linalool exhibited no effect when employed in concentrations as high as 100 ppm. Besides phytofluene, C-carotene was accumu­ lated after application o f sublethal amounts o f active geranyl derivatives. Cell growth and chlorophyll a synthesis were only slightly affected under conditions were carotenoid synthesis was markedly inhibited. 
  Reference    Z. Naturforsch. 38c, 387 (1983); received January 26 1983 
  Published    1983 
  Keywords    Inhibitors, Carotenoid Synthesis, Pseudoionone, Famesol, Famesyl Acetate 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0387.pdf 
 Identifier    ZNC-1983-38c-0387 
 Volume    38 
16Author    Klaus Pfister, U. Lrich, S. ChreiberRequires cookie*
 Title    Comparison of Diuron-and Phenol-Type Inhibitors: Additional Inhibitory Action at the Photosystem II Donor Site  
 Abstract    Inhibitors o f photosystem II reactions from the "diuron-type" and "phenol-type" have been compared regarding their m echanism o f action. "Diuron-" as well as "phenol-type" inhibitors act at the acceptor site o f photosystem II by displacing the secondary acceptor quinone Q B from its binding site. "Phenol-type" inhibitors additionally interfere with the donor site, which is demonstrated in studies o f chlorophyll fluorescence and lum inescence. This m echanism o f action is shown to be similar but not identical to that reported for hydroxylam ine. 
  Reference    Z. Naturforsch. 39c, 389 (1984); received D ecem ber 1 1983 
  Published    1984 
  Keywords    Herbicides, Photosynthesis, Fluorescence, Lum inescence, Inhibitors 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0389.pdf 
 Identifier    ZNC-1984-39c-0389 
 Volume    39 
17Author    Requires cookie*
 Title    Phosphorylation of Coformycin and 2 -Deoxycoformycin, and Substrate and Inhibitor Properties of the Nucleosides and Nucleotides in Several Enzyme Systems  
 Abstract    Under conditions where 2'-deoxycoformycin is enzymatically phosphorylated by wheat shoot phosphotransferase to the 5'-phosphate in 15—20% yield, coformycin is a relatively poor sub­ strate, and is phosphorylated only to the extent of < 5%. However, chemical phosphorylation of coformycin by modifications of the Yoshikawa procedure led to isolation of coformycin-5'-phos­ phate in 20% overall yield. Coformycin-5'-phosphate was characterized by various criteria, including 'H NMR spectro­ scopy. Comparison of the spectrum with that of the parent nucleoside indicated that the nu­ cleotide is predominantly, although not exclusively, in the conformation anti about the glycosidic bond. Like 2'-deoxycoformycin-5'-phosphate, coformycin-5'-phosphate was a feeble substrate of snake venom 5'-nucleotidase, and is hydrolyzed, quantitatively, at only 2% the rate for 5'-AMP. With 5'-AMP analogues as substrate, the 5'-phosphates of both coformycin and deoxycoformycin were poor inhibitors of the enzyme, with K, values > 0.3 mM. The 5'-phosphates of both coformycin and deoxycoformycin do not significantly inhibit adenosine deaminase (K} > 0.2 m M), but are potent inhibitors of adenylate deaminase (Kj < 10"9 m). Neither coformycin nor deoxycoformycin are inhibitors of mammalian purine nucleoside phosphorylase. The stabilities of coformycin, deoxycoformycin, and their 5'-phosphates, have been examined as a function of pH, and nature of the buffer medium. In particular, all exhibit instability in acid and neutral media, but are relatively stable in the vicinity of pH 9. Some biological aspects of the overall results are presented. 
  Reference    Z. Naturforsch. 40c, 710—714 (1985); received March 5/June 3 1985 
  Published    1985 
  Keywords    Coformycin, 2'-Deoxycoformycin, Phosphorylation, 5'-Phosphates, Substrates, Inhibitors 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0710.pdf 
 Identifier    ZNC-1985-40c-0710 
 Volume    40 
18Author    MitkoA. Subchev, JuliusA. Ganev, Otto Vostrowsky, HansJürgen BestmannRequires cookie*
 Title    Screening and Use of Sex Attractants in Monitoring of Geometrid Moths in Bulgaria  
 Abstract    Four candidate sex attractants for geometrid moths have been screened individually and in mixtures. As a result, in addition to the confirmation of the known sex attractants of Operophtera brumata L. and Alsophila aceraria Denis & Schiff (— A. quadripunctata Esper), possible sex attractants for five other geometrid species have also been established. For O. brumata and A. aceraria an inhibitor has been found. For the same species the possibility for seasonal monitoring by means of sex pheromone traps was demonstrated. 
  Reference    Z. Naturforsch. 41c, 1082—1086 (1986); received May 7 1986 
  Published    1986 
  Keywords    Pheromones, Sex Attractants, Geometridae, Polyene Hydrocarbons, Inhibitor 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/41/ZNC-1986-41c-1082.pdf 
 Identifier    ZNC-1986-41c-1082 
 Volume    41 
19Author    Rekha Chaturvedi, M. Singh, P. V. SaneRequires cookie*
 Title    Photoinactivation of Photosynthetic Electron Transport under Anaerobic and Aerobic Conditions in Isolated Thylakoids of Spinach  
 Abstract    The effect o f exposure to strong white light on photosynthetic electron transport reactions o f PS I and PS II were investigated in spinach thylakoids in the absence or presence o f oxygen. Irrespective o f the conditions used for photoinactivation, the damage to PS II was always much more than to PS I. Photoinactivation was severe under anaerobic conditions compared to that in air for the same duration. This shows that the presence o f oxygen is required for prevention o f photoinactivation o f thylakoids. The susceptibility o f water-splitting com plex in photoinactivation is indicated by our data from experiments with chloride-deficient chloro-plast membranes wherein it was observed that the whole chain electron transport from DPC to MV was much less photoinhibited than that from water. The data from the photoinactivation experiments with the Tris-treated thylakoids indicate another photodam age site at or near reaction centre o f PS II. D CM U -protected PS II and oxygen-evolving com plex from p h oto­ inactivation. D C M U protection can also be interpreted in terms o f the stability o f the PS II complex when it is in S2 state. 
  Reference    Z. Naturforsch. 47c, 63—6 (1992); received August 16 1991 
  Published    1992 
  Keywords    Photoinactivation, Anaerobiosis, Inhibitors, Photosynthetic Electron Transport, Trypsinization 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0063.pdf 
 Identifier    ZNC-1992-47c-0063 
 Volume    47 
20Author    M. O. Ilori, O. O. Amund, O. OmidijiRequires cookie*
 Title    Characterisation of a Neutral Protease Produced by Micrococcus luteus  
 Abstract    A proteolytic enzyme produced by a cassava-ferment­ ing strain of Micrococcus luteus was extracted and puri­ fied 50-fold by gel filtration and ion exchange chroma­ tography. The optimum pH for the enzyme was 7.0, the opti­ mum temperature 25 °C, the apparent molecular weight 42 kDa and the K m value, 0.45 mg m l-1 with casein as substrate. The enzyme was stimulated by Ca2+ and Mg2+ but inhibited by Zn2+ and Co2+ ions. Other inhibitors were EDTA, KCN, citric acid and L-cysteine indicating the enzyme to be a metalloprotease. 
  Reference    Z. Naturforsch. 51c, 429—431 (1996); received May 26 1995/January 15 1996 
  Published    1996 
  Keywords    M etalloprotease Purification, Heat Inactivation, Apparent Molecular Weight, Inhibitors 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0429_n.pdf 
 Identifier    ZNC-1996-51c-0429_n 
 Volume    51 
1
2
Next