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Enzymatic Synthesis of Glutamine in Higher Plants

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volumes of chilled acetone in a Waring Blendor at Io C. The suspension was filtered with suction at Io C, and the residue sucked dry in a stream of cold air. The operation was repeated, and the coarse powder was sifted through a screen. The resulting powder was stored in a desiccator at Io C. Active extracts of acetone powders were prepared essentially in the manner described by Speck (10). Unless otherwise indicated, the complete reaction system contained: 0.05 M potassium phosphate buffer (pH 7.0), 0.05 M sodium L-glutamate,

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... This, indeed, has been found to be so (8,29). Glutamine svnthetase has been isolated and purified from plant tissues (9,40) and its existence cannot be doubted. The overall metabolisnm of detached Nicotiana leaves may be summarized thus: ...
Chapter
The spatial relationships of the myriad enzymes concerned in cell metabolism have assumed great significance in our efforts to understand the intergrated economy of the plant cell. During investigations into the intracellular distribution of enzymes, the biochemical activities of the mitochondria have been widely studied.
Article
Preparations of organelles enriched in either chloroplasts or mitochondria were prepared from spinach leaves by a slight modification of the method of Jensen4. Typical results showing the distribution of glutamine synthetase and a number of marker enzymes are shown in Table 1. Considerable glutamine synthetase activity was found in the chloroplast enriched fraction, and the distribution was similar to that of the triose phosphate dehydrogenase (NADP) and alkaline fructose diphosphatase used as chloroplast markers. The glutamine synthetase activity was slight in the mitochondria enriched fraction, and was not associated with fumarase, used as a mitochondrial marker.
These are exciting times in the study of protein synthesis. We are beginning to gain some insight into the mechanism by which amino acids are assembled into the peptide chains of proteins and to achieve some understanding of the way in which information is transferred from nucleus to cytoplasm, there to be used in the construction of the many individual proteins of the cell. The flood of new information and insight concerning protein synthesis has in part come from elegant enzymology and biochemistry applied to the study of the process. In part, and in a large part, however, it has come from a better understanding of the structure of the cell and from improved methods for the separation of cytoplasm into its subcellular constituents. These studies have focused attention upon the microsomes as the engines of protein synthesis. This review will therefore first consider the microsomes—their general role in protein synthesis, their origin and their structure. We shall then go on to the biochemistry and enzymology of protein synthesis insofar as we understand it today. Work on animal tissues and on microbial cells, as well as on plant tissues has contributed to our knowledge of protein synthesis, and although this review is particularly directed toward an understandig of plants, it will be helpful to draw on work with other materials.
Article
acid Ittherefore seemedpossible thatthesynthesis ofdipeptides involving the glutamyl moiety mightoccur byananalogous reaction. Theglutamyl pep- tide, gamma-glutamyl-cysteinyl-glycine (glutathione), isknowntooccur generally inplants. Theenzymatic synthesis ofgamma-glutamyl-cysteine hastherefore beenfirst investigated since this compound constitutes apossi- bleintermediate inthesynthesis ofglutathione. JOHNSTON andBLOCH(4) havealready demonstrated anecessity ofATPforglutathione formation by liver preparations, andSNOKEandROTHMAN(7)havereported theconden- sation ofgamma-glutamyl-cysteine andglycine toformglutathione inthe samesystem. Theenzymesystem usedinthis workconsisted ofdialyzed extracts of acetone powders ofbean(Phaseolus vulgaris) seedlings prepared asprevi- ously described (8).Theenzymewasincubated for60minutes at250C ina reaction mixture consisting of:0.05 M phosphate buffer (pH7.0), 0.01M glutamic acid-2-C14 (specific activity-0.1 mc./mM), 0.01M cys- teine, 0.002 M ATP,0.005 M MgSO4,and0.005 M KCIinatotal volume of5ml.Thereaction wasstopped bytheaddition ofcoldacetone, andthe precipitated protein removedbycentrifugation at5000xg. Thesuper- natant solution wasevaporated todryness underavacuum, andtheresidue wastakenupinasmallquantity ofasolution ofN-ethyl maleimide as described byHANESetal.(3).Thecomponents present inthesolution were nextseparated bypaperchromatography (8).Bestseparation wasobtained withabutanol-acetic acid-water mixture (4:1:1)asthesolvent. Thepres- enceofradioactive material onthechromatogram wasindicated byradio- autography (1), whilenon-radioactive aminoacidsandpeptides were detected withninhydrin. TableIgives Rfvalues obtained inatypical experiment. Itisevident thata radioactive substance hasbeenformed enzymatically whichhasanRfidentical tothatofauthentic gamma-glu- tamyl-cysteine prepared synthetically asdescribed elsewhere (9).Further- 1Thisinvestigation wassupported inpartbythePolychemicals Department, E.I. duPontdeNemoursandCo.
Article
An enzyme has been purified some 50-fold from wheat germ extracts which will catalyze the synthesis of γ-glutamylcysteine from glutamic acid and cysteine. The system has an absolute requirement for adenosine triphosphate (ATP) and for magnesium and potassium ions. No other univalent or bivalent metals could be found to effectively replace magnesium and potassium. The enzyme alone does not catalyze any signifycant exchange of orthophosphate-P32 with ATP, but rapidly catalyzes such an exchange in the presence of glutamate. Cysteine reduces this glutamate-induced exchange. Conversely, ADP32 exchanges with ATP in the presence of the enzyme alone, with the amino acids having only a slight inhibitory effect on this exchange. The enzyme also catalyzes the exchange of cysteine-S35 with γ-glutamylcysteine in the absence of ATP. The nature of the phosphate exchange would seem to preclude the formation of a glutamyl phosphate as an intermediate in the peptide synthesis, but is consistent with the formation of enzyme-bound intermediates.
Article
ZusammenfassungIm Teil I der Arbeit (Bd. 12, S. 27) werden die N-Verbindungen und die Bedeutung ihrer Bindungsart für die Pflanzenernährung besprochen.Genotypische Veränderungen der Proteinmenge und -qualität in Pflanzen sowie auch die Beeinflussung durch Veränderung der Umweltverhältnisse (insbesondere Düngung) werden erörtert.Im Abschnitt über die Bedeutung des Nahrungsstickstoffs für die Tierernährung wird festgestellt, daß nicht nur Menge und Qualität eines Nährstoffs allein wertbestimmend sind, sondern vor allem auchdas Verhältnis zu anderen Futterinhaltsstoffen. Außerdem ist die Anforderung einer bestimmten Tierart an die Qualität seiner Nahrung abhängig von der geforderten Leistung. Die Angaben von Bedarfszahlen für essentielle Aminosäuren sollten immer in Relation zur Rohproteinmenge, nidit mit Bezug auf die Gesamtkost, erfolgen.Die im II. Teil der Arbeit (Bd. 12, S. 88) besprochenen Tierversuche wurden an Ratten durchgeführt und erstrecken sich auf den Vergleich der Bilanz-Methode mit Verfahren, die eine direkte Bestimmung des retinierten Körper-N erlauben. Die Ergebnisse gestatten den Schluß, daß die Wertermittlung von Futtermittelrohproteinen mit gleicher Genauigkeit durch die direkte Körper-N-Analyse (oder auch aus Berechnung aus Wasserbestimmungen im Gesamttier) erfolgen kann (Net Protein Utilization) anstatt durch die Bilanz-Methode (Biologische Wertigkeit). Die Bestimmung der Net Protein Utilization ist technisch einfacher und bezieht die Verdaulichkeit mit ein.Bei alien Versuchen wurde mit Hilfe der N-Bilanz-Methode eine hohere („schein- bare”) N-Retention ermittelt als durch die direkte Körper-N-Analyse („wahre N-Retention”). Dieser Befund erfordert weitere Untersuchungen.Die Eiweißbausteinanalyse als Mittel zur Nahrungswertermittlung von Futtermittelrohproteinen wird im III. Teil der Arbeit beschrieben. Mit Hilfe dieser Methode kann nur ein theoretisch moglicher Futterwert ermittelt werden, der der Nachprüfung durch Tierversuche bedarf, es werden jedoch wertvolle Hinweise auf den Grund eines eventuell vorliegenden Mangels (Fehlen oder zu geringe Konzentration bestimmter essentieller Aminäsauren) erhalten.Das beschrieben: Verfahren kann zu Bausteinanalysen im Gesamtfutter verwendet werden. Es beruht auf einer adsorptiven Gruppentrennung nach Hydrolyse mit nachfolgender papierchromatographischer Auftrennung der Gruppen und Bestimmung der Aminosäuren direkt auf dem Papier. Die Fehlergrenze beträgt ± 10 %.
Chapter
Ammoniak spielt im Leben der Pflanze eine besondere Rolle, weil es in vielen Fällen eine Hauptquelle für den Stickstoffstoffwechsel überhaupt ist oder aus Nitraten durch Reduktion leicht gebildet werden kann oder aus anderen N-Quellen wie z. B. Harnstoff entsteht und weil es ein allgemein auftretendes Produkt der Eiweißdissimilation ist. „Ammoniak ist die erste und die letzte Stufe in den Umwandlungen der stickstoffhaltigen Stoffe in den Pflanzen, Alpha und Omega dieses Prozesses“ (Prjanischnikow 1922).
Chapter
The cellular mechanisms underlying the synthesis and breakdown of highly specific protein structures are of basic interest in many branches of biological study. But, despite the varied attacks which have been made on the problems of protein metabolism, many of the biochemical mechanisms, and especially those concerned in protein synthesis, remain uncertain or obscure. With particular regard to the metabolism of higher plants, valuable reviews have been given by Petrie (1943), McKee (1949), Street (1949), Wood (1953), Steward and Thompson (1954) and Webster (1955).
Chapter
Der überwiegende Teil der Forscher ist heute der Ansicht, daß bei der Assimilation der verschiedenen Formen des Stickstoffs durch die Pflanzen das Ammoniak als aktive Zwischenstufe eine Hauptrolle spielt. Kleine Mengen von Ammoniak sind immer in den Pflanzenorganismen enthalten und zwar unabhängig von der Stickstoffnahrung. Die enzymatischen Systeme und die Vorgänge bei der Assimilation des Ammoniak sind wohlbekannt. Die oxydierten Formen des inorganischen Stickstoffs werden zu Ammoniak reduziert. Bei dieser Totalreduktion des Nitrats sind salpetrige Säure (HNO2), untersalpetrige Säure (H2N2O2) und Hydroxylamin (NH2OH) die möglichen Zwischenstufen (vgl. Chibnall 1939, Vanecko und Frear 1955).
Chapter
Amino acids, both in the free form and as constituents of protein, occupy a central position in the metabolism of all organisms, and the pathways of amino acid metabolism, as far as they are known, are for the most part quite similar from one organism to another. Instances of dissimilarity occur primarily in the ability or inability to synthesize a particular amino acid. Thus, while plants, animals and microorganisms utilize generally the same amino acids for protein synthesis and other metabolic functions, they differ greatly in synthetic capacity. Whereas the plant can produce all the amino acids it requires, animals and many microorganisms must obtain several of the amino acids preformed, in their food or culture medium. Unfortunately, since the biosynthesis of amino acids has received less attention in plants than in other organisms (the amides are a notable exception to this statement), it will be necessary in this review to draw heavily on findings from animals and microorganisms.
Chapter
Der vorliegende Berichtsabschnitt ist durch ein weiteres Ansteigen der vielfältigen Untersuchungen auf dem Gebiet der Strahlenbiologie gekennzeichnet. Es erscheint praktisch unmöglich, selbst wichtige Arbeiten gebührend zu berücksichtigen, und es sind Beschränkungen erforderlich. Trotz der vielen Untersuchungen zeigt sich, daß wir von einem Verständnis der Wirkung der verschiedenen Strahlungen im lebenden Gewebe noch weit entfernt sind. Nachdem in den letzten Jahren bekannt wurde, welche hervorragende Bedeutung neben den direkten Trefferwirkungen die indirekten Strahleneffekte (vgl. Fortschr. Bot. 15) besitzen, hat sich deren Untersuchung sehr stark ausgedehnt, und die Wendung des Interesses der biologischen Strahlenforschung von rein physikalischen Gesichtspunkten zur chemischen Betrachtungsweise ist augenfällig [vgl. z. B. Gray 1954 (3), (4); oder auch Wels (2)]. Aber bereits der Ausgangspunkt des ganzen Problems, die Radiochemie des Wassers und der einfachsten Lösungen, ist noch keineswegs wirklich geklärt. So ist es nicht verwunderlich, daß die viel komplexeren Verhältnisse in Zellen und Geweben zwar in breitester Front untersucht wurden, im ganzen aber erst ein Anfang der ursächlichen Aufklärung der Strahlenwirkung erreicht worden ist. Auch die Abhängigkeit der Strahlenwirkung von den vor, während und nach der Bestrahlung herrschenden physikalischen, chemischen und biologischen Bedingungen, wie Temperatur, Anwesenheit der verschiedensten Stoffe, dem Entwicklungszustand der untersuchten Zellen und Gewebe usw., ist immer stärker Gegenstand der Forschung geworden.
Chapter
Die pflanzliche Trockensubstanz setzt sich grob gesprochen zu etwa 80 % aus den Elementen Kohlenstoff, Sauerstoff und Wasserstoff zusammen. Wie aus der Zusammenstellung der zur Bildung von 100 bushels Mais erforderlichen Mengen der einzelnen Elemente oder N?hrstoffe hervorgeht (Tab. 61), haben davon Sauerstoff und Kohlenstoff dem Gewicht nach den h?chsten Anteil.
Chapter
When living plant protoplasm is observed with a microscope, the protoplasmic inclusions—nuclei, plastids, mitochondria, ergastic droplets, and other smaller particles ranging down to the limits of light microscopy—often can be seen in active cyclosis. The sluggish manner in which the inclusimis change their position as the protoplasm courses around the cell suggests that they are being carried along by a somewhat viscous matrix, which appears visibly different from the vacuole. The hyaline character of the matrix also suggests that it is homogeneous. However, this impression of homogeneity disappears when the matrix is examined with the ultramicroscope, for some particles measuring about 0.1 micron and others barely detectable by this instrument, that is, about 50 to 100 Å in diameter, have been discerned (Gaidukov 1906). Aside from the nucleus, the non-vacuolar portion of the protoplasm is the cytoplasm of the cytologist.
Chapter
Transamination represents a class of reaction wherein the amino nitrogen of an amino acid (donor) is transferred to aminate the carbonyl group of a keto acid (acceptor). The acceptor now becomes an amino acid whereas the donor becomes a keto acid. Transamidation involves the transfer of −NH2 from a carboxamide group to a suitable acceptor. Transamination is far better understood than transamidation, but both types of transfer reaction appear to be of general importance in the metabolism of plants and other organisms. The role of transamination in amino acid synthesis is discussed in the chapter “The synthesis of amino acids in plants”, p. 224.
Chapter
The most generalized of the plastids is the chloroplast. Because of the importance of the chloroplast it will be the plastid type whose properties will be considered here in detail. In this review, two general aspects of the biology of the chloroplast will be considered, namely: the structure of the chloroplast and its relation to photosynthetic function; and the origin, growth, and inheritance of this cytoplasmic body. Since the editors plan to present a section on the chemical composition of the chloroplast in another volume of the Handbook, considerations of the proteins, enzymes, pigments, starch, etc. of the chloroplast have been omitted except as they may be pertinent to the immediate discussion.
Chapter
Photosynthesis is highly dependent on structure. In higher plants, the photosynthetic apparatus is localized in chloroplasts. In certain algae and photosynthetic bacteria such chloroplasts are absent. For a long time, it has been believed that in these organisms the photosynthetic pigments are homogeneously distributed throughout the cytoplasm. Electron microscope studies, however, revealed that, also here, a structured photosynthetic apparatus, albeit different from a “true” chloroplast, occurs. Unfortunately, it is not an easy task to define a “true chloroplast”. The classical definition states that the chloroplast is a chlorophyll containing chromoplast. The chromoplasts, together with leucoplasts, belong to the plastids. Plastids, in their turn, are autonomous cytoplasmatic bodies. Though this definition does not contain much information about a chloroplast, it may seem to be useful for classification of this organelle. However, in certain organisms, such as blue-green algae, diatoms and photosynthetic bacteria, things become difficult to classify. Either the structure in question looks incomplete as compared with that of higher plants or its dimensions are submicroscopic, whereas it is tacitly accepted that chloroplasts are perceptible under the light microscope. Thus it seems desirable to reconsider the present definition. However, before attempting to do so, the data concerning both chemical and physical composition of the chloroplast will be reviewed.
Chapter
Auch der Zustand der nichtwachsenden, aber lebenden und aktiven Zelle ist, wie wir wissen, dynamisch charakterisiert, als Gleichgewichtszustand, in dem der dauernd ablaufende Stoffabbau durch eine Synthese gleichen Umfanges bilanzmäßig kompensiert ist (Rittenberg und Mitarbeiter 1939, Vickery und Mitarbeiter 1939, Hevesy und Mitarbeiter 1940, Schoenheimer 1942, MacVicar und Burris 1948, Mazia und Prescott 1955 u. a.). Überwiegen die Synthesen die abbauenden Vorgänge, so arbeitet die Zelle mit Stoffgewinn, sie wächst. Diese Art des Wachstums, die wir, soweit wir nur die Zunahme der plasmatischen Zellbestandteile ins Auge fassesn, als Plasmawachstum bezeichnen, ist die fundamentale, die gewöhnlich auch den anderen Wachstumsformen, dem Teilungswachstum und dem Streckungswachstum, vorauszugehen hat, diese auch zum Teil noch begleitet.
Article
One of the major recent advances in cellular architectonics, the spatial and structural organization of reactions and processes, is the elucidation of the role of mitochondria in cell metabolism. Plant cell is not simply a bag of haphazardly arranged enzymes. The cell particulates possess a high degree of structural and functional organization, which is, under certain conditions, very labile. The fundamental processes carried out by the mitochondria appear to be the terminal transfer of electrons, the coupling of energy-trapping mechanisms (phosphorylations) to oxidations, and the Krebs cycle reactions and the numerous ancillary processes that eventually funnel through the cycle. In spite of the remarkable autonomy of the mitochondria, the overall activities of the cell are the result of intimate interactions among the various cellular components. Glycolysis involves the plastids, the soluble fraction, and possibly the nucleus as well as the mitochondria1 enzymes. Certain enzymes involved in the Krebs cycle (e.g., malic dehydrogenase) and in hydrogen transfer (e.g., cytochrome reductase) are not confined entirely to the mitochondria. The mitochondria interact with the nucleus in phosphorylation, with the chloroplasts in photosynthesis, and with the microsomes in protein synthesis. In close relation to the outer cell boundary, the mitochondria may participate actively in the movement of substances into the cell or in the growth of the cell wall.
Article
Glutamine isthefirst major organic product ofassimilation of"3NH41 bytobacco (Nicotians tabacuL.cv.Xanthi) ceUls cultured onnitrate, urea, orammonium succinate asthesole source ofnitrogen, andof13N03- bytobacco cells cultured onnitrate. Thepercentage oforganic 13Nin glutamate, andsubsequently, alanine, increases withincreasing periods of asshimlation. 13N03, usedforthefirst timeinastudy ofassimilation of nitrogen, waspurified bynewpreparative techniques. During pulse-chase experiments, there isadecrease inthepercentage of13Ninglutamine, and aconcomitant increase inthepercentage of13Ninglutamate andalanine. Methionine sulfoximine inhibits theincorporation of13Nfrom13NH4' into glutamine moreextensively thanitinhibits theincorporation of13Ninto glutamate, withcelsgrownonanyofthethree sources ofnitrogen. Azaserine inhibits glutamate synthesis extensively when13NH4' isfedto cells cultured onnitrate. Theseresults indicate that themajor routefor assimilation of13NH4' istheglutamine synthetase-glutamate synthase pathway, andthat glutamate dehydrogenase also plays arole, butaminor one.Methionine sulfoximine inhibits theincorporation of13Nfrom13NO3- into glutamate morestrongly thanitinhibits theincorporation of13Ninto glutamine, suggesting that theassimilation of13NH4' derived from13N03- maybemediated solely bytheglutamine synthetase-glutamate synthase pathway.
Article
C14-labelled substrates were supplied to leaves, and the labelling patterns in derived amino acids were examined. A new technique is described for the ninhydrin decarboxylation of amino acids separated on paper chromatograms, making use of the Dynacon electrometer. Succinate-1,4-C14, succinate-2,3-C14, pyruvate-1-C14, pyruvate-2-C14, pyruvate-3-C14, C14O2, and glutamate-1-C14 were supplied to wheat leaves, and the total C14 and carboxyl-C14 in alanine, aspartate, glutamate, asparagine, and glutamine were determined. The results indicated that the amino acids and amides were formed mainly from the corresponding Krebs cycle intermediates. Carbon entered the Krebs cycle mainly by decarboxylation of pyruvate, but partly by its carboxylation. Extensive cycling did not occur. Various other suggested pathways, including the conversion of succinate to glutamic acid via succinic semialdehyde and γ-aminobutyrate followed by carboxylation, did not occur.When glucose-UL-C14 was supplied to pea or bean seedlings, the labelling pattern in alanine and glutamine indicated their derivation from glucose via glycolysis and Krebs cycle pathways. However, the pattern in asparagine indicated that it may have been formed from products of glyoxalate cycle.
Article
In the enzymic synthesis of acetyl-coenzyme A, oxygen from acetate appears in the phosphate group of the adenylate formed. In the enzymic synthesis of glutamine, oxygen from glutamate appears in the inorganic phosphate formed. These and other observations support the hypothesis that, in enzymic synthesis coupled to adenosine triphosphate degradation, oxygen transfer occurs from the substrate to a moiety cleaved from the adenosine triphosphate.
Article
Italian ryegrass (Lolium multiflorum) S22, grown in Mg-deficient soil in pots, was given 40 and 160 mg N/kg of soil as ammonium nitrate or as ammonium sulphate treated with a nitrification inhibitor and 0, 20 and 40 mg Mg/kg of soil as magnesium sulphate. Yields of grass given the larger dressing of N were greater with ammonium nitrate than with ammonium sulphate. The magnesium treatments significantly increased yields only of the third cut given the most N when concentrations of Mg in dry matter were 0.07% or less. Magnesium fertiliser had little effect on the production of reducing sugars and sucrose but markedly increased fructosan and percentages of chlorophyll in grass of the third cut given the larger dressing of N. Non-protein nitrogen was much greater with ammonium sulphate than with ammonium nitrate nutrition. With both forms of N fertiliser, this fraction accumulated in grass grown without added Mg, but it decreased when Mg-deficiency was corrected. The percentage distribution of N in the free amino acid pool varied with the form of N fertiliser and the Mg treatments. With grass given ammonium nitrate, free amino acids predominated over amides; the reverse was true for grass given ammonium sulphate. The main effect of adding Mg was to decrease glutamine and to increase the percentages of some free amino acids, especially alanine and γ-aminobutyric acid. About half of the soluble organic N in grass given ammonium nitrate was unaccounted for as amino acids and amides with all the Mg treatments; this N fraction was much less in grass given ammonium sulphate, but it increased with increasing magnesium fertiliser.
Article
Glutamine is the first major organic product of assimilation of (13)NH(4) (+) by tobacco (Nicotiana tabacum L. cv. Xanthi) cells cultured on nitrate, urea, or ammonium succinate as the sole source of nitrogen, and of (13)NO(3) (-) by tobacco cells cultured on nitrate. The percentage of organic (13)N in glutamate, and subsequently, alanine, increases with increasing periods of assimilation. (13)NO(3) (-), used for the first time in a study of assimilation of nitrogen, was purified by new preparative techniques. During pulse-chase experiments, there is a decrease in the percentage of (13)N in glutamine, and a concomitant increase in the percentage of (13)N in glutamate and alanine. Methionine sulfoximine inhibits the incorporation of (13)N from (13)NH(4) (+) into glutamine more extensively than it inhibits the incorporation of (13)N into glutamate, with cells grown on any of the three sources of nitrogen. Azaserine inhibits glutamate synthesis extensively when (13)NH(4) (+) is fed to cells cultured on nitrate. These results indicate that the major route for assimilation of (13)NH(4) (+) is the glutamine synthetase-glutamate synthase pathway, and that glutamate dehydrogenase also plays a role, but a minor one. Methionine sulfoximine inhibits the incorporation of (13)N from (13)NO(3) (-) into glutamate more strongly than it inhibits the incorporation of (13)N into glutamine, suggesting that the assimilation of (13)NH(4) (+) derived from (13)NO(3) (-) may be mediated solely by the glutamine synthetase-glutamate synthase pathway.
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Inaug.-Diss.--Zürich. Vita. Bibliography, p. 56-59.
Article
The experiments reported in this paper concern the mechanisms involved in plant respiration, particularly those involved in the oxidation of pyruvate. The interest of such a study lies in the fact that although pyruvate is well established as an intermediate in the respiratory oxidation of hexose by plant tissues,(1) it has not heretofore been possible to bring about the further oxidation of pyruvate in vitro by any enzyme system of plant origin.
The enzymatic svnthesis of glutamine, a reaction utilizing adenosine triphosphate
SPECK, J. F. The enzymatic svnthesis of glutamine, a reaction utilizing adenosine triphosphate. Jour. Biol. Chem. 179: 1405-1426. 1949.
A specific micromethod for the determnination of acyl phosphates
LIPMANN, F. and TUTTLE, L. C. A specific micromethod for the determnination of acyl phosphates. Jour. Biol. Chem. 159: 21-28. 1945.
Glutamine-synthesizing system of Staphylococcus aureus: its inhibition by crystal violet and methionine-sulphoxide
ELLIOTT, WV. H. and GALE, E. F. Glutamine-synthesizing system of Staphylococcus aureus: its inhibition by crystal violet and methionine-sulphoxide. Nature 161: 129-130. 1948.