bluuebunny/crossref_metadata_2025 huggingface dataset:
Dehydrogenasen-Darstellung im elektronenmikroskopischen Zellbild
Authors: Fasske E. , Gerlach U. , Steins I. , Themann H.
Published: February 2015

Mit dem Ziel der Sichtbarmachung von Dehydrogenase-Aktivitäten (Succino-Dehydrogenase, DPN- und TPN-gebundenen Dehydrogenasen) im elektronenmikroskopischen Zellbild wurden geprüft: 1. Der Einfluß verschiedener Fixierungsmittel auf Zellstruktur und Enzymaktivität, 2. Form, Dichte und Größe der bei Verwendung von Nitro-BT als Wasserstoffakzeptor ausfallenden Diformazane und 3. Lokalisation von einzelnen Dehydrogenasen. — Nach den quantitativen Messungen des Aktivitätsabfalles der Enzyme durch die Fixantien kommt zur Vorfixation Hydroxyadipaldehyd in Frage. Dieser Aldehyd mindert die Dehydrogenase-Aktivität zwar um mehr als 50%, doch ist der verbleibende Aktivitätsrest für die Reaktion ausreichend. Glutaraldehyd ist ungeeignet. — Bei in vitro-Reduktion des Nitro-BT mittels Wasserstoff und elektronenmikroskopischer Untersuchung der dabei ausfallenden Diformazane finden sich 0,3 — 0,6 μ große, elektronendichte, längsovale Plättchen. Diese sind mit den Depositen innerhalb der Zellen bei der Inkubation auf einzelne Dehydrogenasen identisch. Die Plättchen unterscheiden sich elektronenoptisch deutlich von unspezifischen, nadelförmigen Niederschlägen. Die Diformazanplättchen markieren intramitochondriale Dehydrogenase-Aktivitäten zwischen den Cristae mitochondriales. Die Deposite selbst sind zu groß, um auf den Leisten einzelne Dehydrogenasen abzugrenzen.
Untersuchung des gelösten Tabakmosaikvirus-Proteins mittels der Röntgen-Kleinwinkelstreuung unter Verwendung der Absolutintensität
Authors: Anderer F. A. , Kratky O. , Lo R.
Published: February 2015

Das Verhalten von TMV-Proteinmolekülen in verschiedenen Lösungsmitteln wurde untersucht. In Essigsäure liegen partiell denaturierte Monomere vom Mol.-Gew. 17 300 vor. In 0,01-n. NaOH bilden sich aus mehreren Monomeren stäbchenförmige Aggregate. In 36-proz. Harnstofflösung wird das TMV-Protein völlig denaturiert. Im Grenzfall unendlicher Verdünnung findet man isotrope monomere Fadenknäuel. Bei höherer Proteinkonzentration lagern sich diese in komplizierter Weise zu Aggregaten zusammen, die bei 2% Proteingehalt bereits aus durchschnittlich fünf Monomeren bestehen.
Atmung, Glykolyse und Überlebensdauer von Monolayer-Gewebekultur-Zellen nach Verbringen in Suspension
Authors: Luthardt Th. , Fischer W.
Published: February 2015

The suspension of cells from monolayer cultures for manometric measurements provides a technical simplification and has therefore become a frequent manipulation in such studies. In the experiments described respiration, aerobic glycolysis and lifespan of the cells after their transition from the intact cell-layer to the suspension were studied.

The glycolytic rate remains unchanged in the suspension, if the culture medium was not changed. Cultures without glycolysis do not glycolyse in the suspension either.

The respiratory rate is independant of glycolysis. Under the conditions used it is somewhat accelerated in cell-suspensions. The lifespan of the cells is considerably reduced. After 5 to 10 hrs. a distinct loss of respiratory rate can be noted, which does not take place in cell-layers.

The reproducability of the results in cell suspensions is not sufficient.

Considered in the light of these findings cell suspensions of monolayer cultures seem only conditionally suitable for manometric measurements and should only be used when measurements with intact cell-layers are not possible.
Über Reaktionen zwischen Phosphortrichlorid und Cyclohexen unter dem Einfluß von Y-Strahlung und von Wärme
Authors: Wunder K. , Drawe H. , Henglein A.
Published: February 2015

1-chlorocyclohexyl-phosphorus dichloride is formed in a Kharasch type chain reaction when γ-rays act on mixtures of phosphorus trichloride and cyclohexene. The G-value is proportional to the reciprocal square root of the dose rate and reaches a maximum at 100°C. The activation energy of the rate determining step PCl2C6H10 · +PCl3→PCl2C6H10Cl+PCl2 · was found to amount to 6, 7 kcal/mole. At higher temperatures, the yield strongly decreases since another chain reaction predominates which produces cyclohexyl-phosphorus dichloride. The two chains have a common propagation step. 1-chlorocyclohexyl-phosphorus dichloride and cyclohexyl-phosphorus dichloride are also thermally formed at temperatures above about 150°C.
N-Oxyde von Purin-Cobamiden: 1 -N-Oxy-2-methyl-adenin-cobamid und 1 -N-Oxy-adenin-cobamid
Authors: Scharf Helmut , Friedrich Wilhelm
Published: February 2015

Adenin-cobamid (Pseudovitamin B12) und 2-Methyladenin-cobamid (Faktor A) werden mit Monoperphthalsäure in Dimethylformamid im Purin-Anteil des Moleküls zu den entsprechenden 1-N-Oxyden oxydiert. Durch Abbau von 1-N-Oxy-2-methyl-adenin-cobamid (1-N-Oxy-Faktor A) werden 1-N-Oxy-2-methyl-7-α-ᴅ-ribofuranosyl-adenin und 1-N-Oxy-2-methyl-adenin erhalten. Diese werden außerdem durch direkte Oxydierung des Nucleosides bzw. der Base von Faktor A dargestellt.
137Cesium Body Burden and Its Variation in 23 Norwegian School Boys
Authors: Madshus Kjell , Strømme Aksel
Published: February 2015

Twentythree boys from a school in Oslo, born in the years 1945, 1946 and 1947, have been studied with regard to their 137Cs body burden and potassium content. Their average 137Cs body burden increased from 24,2 nC in March 1963 to 46,1 nC in October 1963 and then more slowly to 49,3 nC in March 1964 (or in the ratio 137Cs/K 178, 338, 357 respectively).

The 137Cs body burden which is relatively high compared to what has been found in other countries is partly due to the high concentration of 137Cs in the milk. Those with a large milk consumption seem to have somewhat higher 137Cs body burdens than the others.
Über den Einbau von 5.7.4′-Trihydroxyflavanon-[2.6.8.10-14C4] in Cyanidin und die Isoflavone Biochanin-A und Formononetin
Authors: Patschke Leni , Barz Wolfgang , Grisebach Hans
Published: February 2015

Phloroglucinol- [2.4.6-14C3] was synthesized from ethyl malonate- [2-14C] and condensed with p-carbethoxycoumaryl chloride; the resulting product was saponified to form 5.7.4'-trihydroxyflavanone- [6.8.10-14C3] (II). The latter compound was mixed with 5.7.4′-trihydroxyflavanone-[2-14C] to yield the desired 5.7.4'-trihydroxyflavanone-[2.6.8.10-14C4] (III). Administration of a sample of III in which the activity ratio ring A/C-2 was 1: 2.04 to red cabbage seedlings led to a cyanidin with an activity ratio ring A/C-2 of 1: 2, as was shown by degradation of the cyanidin to phloroglucinol and protocatechuic acid. This result proves that III is incorporated intact into cyanidin. After administration of III to chana germ (Cicer arietinum) Biochanin A (5.7-dihydroxy-4′-methoxyisoflavone) with an activity ratio of 1:2.24 was obtained. In contrast, there was only a small amount of incorporation of III into formononetin (7-hydroxy-4'-methoxyisoflavone), and the activity ratio fell to 1 : 7. These results prove the intact and specific incorporation of III into Biochanin A.

When II is fed to Cicer arietinum about 3% of the total activity is found in the respiratory carbon dioxide after 48 hours. From this observation it can be concluded that the plant is able to degrade ring A of II.
Die lichtabhängige Ausbildung der Zellkerne in den Vorkeimen von Dryopteris filix-mas bei Hemmung der Proteinsynthese
Authors: Bergfeld Rainer
Published: February 2015

It has been shown in a number of papers that the young gametophytes of ferns, e. g. Dryopteris filix-mas, will grow differently under red and under blue light. In red light these sporelings grow as filaments whereas under blue light they form two-dimensional normal prothallia. - The development of the sporelings can be inhibited by the application of methyl-tryptophane. The process of cell division is blocked by this treatment. The blue grown sporelings are much more sensitive than the red grown one.

Under the influence of the antimetabolite methyl-tryptophane the nuclei will swell in both types of sporelings to about the same extent. The application of tryptophane reverses the effects of the antimetabolite on nuclear swelling, cell division and development in general. In the case of the blue grown sporelings much higher concentrations of tryptophane were needed to reverse the inhibition mediated by methyl-tryptophane.

It is assumed that the application of methyl-tryptophane leads to a disintegration of protein and cell metabolism. The transport of substances from the nucleus to the cytoplasm is blocked under these conditions. The result is an accumulation of material in the nucleus which leads to swelling and finally to an inactivation of the nucleus as far as cell division and cell differentiation are concerned. The application of tryptophane gradually leads to a reconstitution of the normal cell metabolism. The swelling of the nucleus is reversed. Apparently the flow of material from the nucleus to the cytoplasm is taken up again which results in normal cell differentiation and mitotic activity.
Die Komplexbildung zwischen Molybdationen und Perjodsäure I
Authors: Jahr Karl Friedrich , Fuchs Joachim , Wiese Günther
Published: February 2015

Mit Hilfe koindizierter Titrationen, durch Variation der Konzentration eines Reaktionspartners und mit einer mathematischen Analyse der Titrationsergebnisse wird die Komplexbildung zwischen Polymolybdat und Perjodsäure bzw. Natriumperjodat untersucht. Dabei werden folgende Heteropolyanionen nachgewiesen:

[JΜο6O24]5⊖, [ΗJΜο6O24]4⊖, [H2JMo6O24]3⊖, [H3JMo6O24] 2⊖, [H4JMo6O24] 1⊖.
Die Umwandlung von 3.5.7.4′-Tetrahydroxyflavanon (Dihydrokämpferol) in Quercetin und Cyanidin beim Buchweizen
Authors: Patschke Leni , Barz Wolfgang , Grisebach Hans
Published: February 2015

3.5.7.4′-Tetrahydroxyflavanone-[T] (dihydrokaempferol-[T]) (I) or 3.5.7.4′-Tetrahydroxyflavone-[T] (kaempferol-[T]) (II) together with phenylalanine-[1-14C] as “internal standard” was fed to buckwheat seedlings and the 14C and tritium activity was determined in the isolated quercetin and cyanidin. The results prove that I but not II is a very efficient precursor for quercetin and cyanidin and that the introduction of the 3′hydroxyl group can take place with I but not with II as the substrate. It can be concluded that dihydrokaempferol is a common precursor for both quercetin and cyanidin in buckwheat seedlings.
Darstellung hoch gereinigter Glutamat-Pyruvat-Transaminase aus Hundeleber und ihre Wirkung auf die anaerobe Glykolyse der Ehrlich-Mäuseascites-Carcinomzelle
Authors: Noll Franz
Published: February 2015

Es wird ein Verfahren zur Darstellung hoch gereinigter Glutamat-Pyruvat-Transaminase beschrieben. Die anaerobe Glykolyse in Ehrlich-Mäuseascites-Carcinomzellen wird durch hoch gereinigte GPT ebenso gehemmt wie durch Leberextrakt, wenn die gleiche Konzentration an GPT-Einheiten eingesetzt wird.
Chlorophyllbestimmungen an Pflanzen mit Plastiden-„Rückmutationen”
Authors: Michaelis P. , Fritz H. G.
Published: February 2015

Bei Epilobium sind an farblosen Ästen geninduzierter Plastidenschecken „Rückmutationen“ beobachtet worden, nach denen einzelne farblose Plastiden wieder ergrünen konnten. Die Farbstoffzusammensetzung von 3 Pflanzen mit solchen „Rückmutationen“ entsprach völlig der der normalen Ausgangssippe. Die Größe der sekundär ergrünungsfähigen Plastiden, ihre Wechselbeziehungen zu den farblosen Plastiden der Primärmutation, ebenso aber auch in einem Falle der Habitus der Pflanzen, können gegenüber der Norm abgeändert sein. Es ist zu vermuten, daß Primär- und Sekundärabänderungen nicht in die Farbstoffbildung eingreifen, sondern daß sie die Plastidenstruktur verändern und dadurch nur mittelbar den Farbstoffgehalt beeinflussen.
Eine Methode zur autoradiographischen Darstellung hydrophiler Substanzen in biologischem Material
Authors: Werner Gottfried , Werner Helga , Bosque Pedro G. , Quevedo José Carreres
Published: February 2015

Mit der beschriebenen autoradiographischen Methode lassen sich auch niedermolekulare hydrophile Substanzen, die mit Radioisotopen markiert sind, darstellen. Einige Beispiele zeigen die Leistungsfähigkeit des Verfahrens.
Aufnahme von 22Na in die Zellkerne der Speicheldrüsen von Chironomus thummi
Authors: Lezzi Markus , Kroeger Heinrich
Published: February 2015

The in vivo and in vitro uptake of 22Na from the hemolymph into cell nuclei of larval salivary glands was measured and compared. The uptake of 22Na in vivo follows approximately a saturation curve. The respective in vitro curve has a much steeper slope during the first 8 min and this phase is followed by an interval during which the 22Na content of the nuclei decreases (8 to 16 min). After the 16th min it increases again to reach a nuclear 22Na content approximately twice as high as that of nuclei in vivo at 60 minutes. The uptake curves are discussed in relation to recent findings on the induction of puffs in polytene chromosomes by inorganic ions.
Die Schmelzelektrolyse von Ammoniumhydrogenfluorid, besonders als Quelle für Distickstoffdifluorid N2F2
Authors: Schmeisser M. , Sartori P.
Published: February 2015

Bei der Schmelzelektrolyse von NH4F · HF entsteht neben NF3 auch Distickstoffdifluorid N2F2. Beide Substanzen können erst nach Zerstörung von gleichzeitig mitentstandenem NHF2 gefahrlos isoliert werden. Chemische und physikalische Eigenschaften des N2F2 werden mitgeteilt.
Infrarotspektrum, Elektronen-Absorptionsspektrum und HMO-Rechnung 4.5-Dioxo-2-thioxo-1.3-dithiolan C3O2S3
Authors: Müller A. , Krebs B. , Ahlrichs R.
Published: February 2015

The infrared and electron absorption spectra of 4.5-dioxo-2-thioxo-1.3-dithiolane are reported and discussed. Using the HMO method, π electron densities, π bond orders, the transition energy EN→v1 and the total π electron energy are calculated.
Untersuchungen zur Stoffwechselregulation der Leberzelle: II. Mechanismus der Hemmung der RNS-Synthese
Authors: Frank Werner
Published: February 2015

Die schwach basischen Hemmstoffe aus dem Cytoplasma erwachsener Leberzellen können die DNS-abhängige RNS-Synthese im Zellkern blockieren. Dies wird gezeigt durch die Kinetik der Einbauhemmung von radioaktivem Uridin in die säureunlösliche RNS von embryonalen Zellen, den Konzentrations-Anstieg von radioaktivem Hemmerprotein im Zellkern sowie durch Einbauversuche mit Zellkernen und den Nucleosidtriphosphaten. Der in-vitro-Einbau von ATP in die säureunlösliche RNS im E. coli-RNS-Polymerasesystem wird gehemmt, durch Zentrifugation in der Ultrazentrifuge läßt sich ein DNS-Proteinkomplex sedimentieren. Aus gereinigten Zellkernen der Leber erwachsener Ratten läßt sich mit isotonischer Kochsalzlösung eine hemmende Proteinfraktion extrahieren, die nach ihren bisher bekannten Eigenschaften mit der Cytoplasmafraktion identisch ist; ebenso enthalten Nierenzellen der Ratte hemmende Proteine, jedoch ist die Wirkung auf embryonale Leber- und Asciteszellen wesentlich schwächer. In Tumorzellen ist eine entsprechende Cytoplasma-Proteinfraktion nur in geringer Menge vorhanden. Das Cytoplasma embryonaler Leber hemmt die RNS-Synthese von embryonalen Leberzellen nicht.
Intramolekulare Wasserstoffverschiebung in der Hexosephosphatisomerase-Reaktion bei der photosynthetischen Stärkebildung in Chlorella
Authors: Dorrer Hans-Dieter , Fedtke Carl , Trebst Achim
Published: February 2015

Chlorella pyrenoidosa was illuminated in the presence of glucose and fructose echa having carbon-14 and tritium markers. Starch and sucrose were degraded to obtain the intramulocular distribution of 14C and tritium. Glucose-1-14C-2-T was incorporated into the glucose of starch and into the glucose moiety of sucrose without change of the T/14C ratio. Fructose-1-14C-1-T (labelled stereospecifically in the isomerase position) was incorporated into starch, yielding predominately glucose-1-14C-2-T, whereas fructose-1-14C-1-T (labelled in the nonisomerase position) gave mainly glucose-1-14C-1-T.

The results, in particular the transfer of tritium from C-1 of fructose to C-2 of glucose, are interpreted as being a strong indication for an intramolecular hydrogen transfer in the hexosephosphat-isomerase reaction in a multienzyme system of the photosynthetic starch biosynthesis in vivo, shielding the hexoses of T-exchange reactions with water.
Spectrophotometric Determination of Ionisation Quotients of Hydroxytriazenes and the Effect of Substituents on p Ka Values
Authors: Dugar S. M. , Sogani N. C.
Published: February 2015

Hydroxytriazenes are very weak acids. The conventional potentiometric and conductometric method cannot be employed for determining their ionisation constants. However, these compounds show a distinct colour change in acid and alkaline media. Ultra-violet absorption studies of these compounds have been made1. The absorption maximum at 305 mµ of 3-hydroxy-3-methyl-1-phenyltriazene shifts to 335 mµ in an alkaline solution. The following equilibrium possibly exists:

(molecular form, absorption peak at 305 mµ)

(anion form, absorption peak at 335 mµ)

This change in absorption maximum with PH has been used in determining the ionisation constants of fourteen hydroxytriazenes employing Robinson’s spectrophotometric method
Über die osmiophilen globulären Lipideinschlüsse der Chloroplasten
Authors: Lichtenthaler Hartmut K. , Sprey Benno
Published: February 2015

The electromicroscopical structure and quinone composition of the osmiophilic, globular, lipiderich plastid inclusions were investigated in several plants. The localisation of the osmiophilic globuli in the plastid stroma and their behaviour toward fixation agents are described. The isolated globuli - here termed plastoglobuli - contain high amounts of lipophilic chloroplasts quinones and apparently no chlorophylls or carotenoids. There exist considerable differences in the relative quinone concentrations of chloroplasts and isolated plastoglobuli. The possible function of plastoglobuli is discussed.
Mitteilungen über lamellare Strukturproteide VI
Authors: Wyk Doris van
Published: February 2015

From chloroplasts of Antirrhinum majus and Spinacia oleracea the structural proteids were isolated with anhydrous formic acid. These glycoproteids contain 3 - 5% carbohydrates. After hydrolysis the sugar constituents were examined by thin-layer- and gas-liquid chromatography. The sugars identified were galactose, glucose, mannose and xylose; galactose was found to be present as the predominant sugar. The carbohydrates of the soluble structural proteid have another sugar composition than those of the insoluble lamellar proteid of chloroplasts.
Urey-Bradley -Kraftkonstanten von tetraedrischen Oxoanionen der Übergangsmetalle in der höchsten Wertigkeitsstufe
Authors: Müller A. , Ahlrichs R. , Krebs B.
Published: February 2015

Mit Hilfe der FG-Matrix-Methode von Wilson werden die Kraftkonstanten K, H, F und F′ des Urey-Bradley- Potentials von tetraedrischen Oxoanionen der Übergangsmetalle in der höchsten Wertigkeitsstufe berechnet. Es wird gezeigt, daß die Abstoßungskonstanten F für chemisch nicht unmittelbar verbundene Atome nicht durch Kräfte erklärt werden können, die sich aus einem Lenard-Jones- Potential ableiten.
Über Diazoverbindungen, XXV. Mitteilung
Authors: Müller Eugen , Renner R. , Rundel W.
Published: February 2015

Der Lichtzerfall des Diazomethans in Cyclohexan, Mischungen von Cyclohexan/Cyclohexen und in reinem Cyclohexen zeigt einen übereinstimmenden kinetischen Verlauf; dies deutet auf einen gleichartigen Mechanismus aller drei Reaktionen, offenbar den Carbenmechanismus.

Der thermische Dunkelzerfall des Diazomethans in Cyclohexan verläuft nach einer Reaktion erster Ordnung mit einer Halbwertszeit von ca. 74 Stunden.

Sauerstoff erhöht die photochemische Zerfallsgeschwindigkeit des Diazomethans in Cyclohexan auf das Sechsfache.
Über den Stoffwechsel von Keto-Carotinoiden in niederen Krebsen
Authors: Czygan Franz-Christian
Published: February 2015

Composition and metabolism of carotenoids in Daphia pulex and in Artemia salina (from California, Utah, Canada) have been studied. Daphnia contains canthaxanthin and echinenone mainly. The typical pigment of Crustaceae, astaxanthin, is absent. Eggs and freshly hatched nauplii of Artemia from California and Utah have the same qualitative composition of carotenoids as Daphnia. The strain from Canada contains traces of astacene in addition. Artemia has been fed on bakers’ yeast and on algae containing astaxanthin, canthaxanthin, echinenone, lutein, β-carotene, and other polyenes. These experiments demonstrate that Artemia is unable to store or to synthesize astaxanthin — contrary to canthaxanthin and echinenone — from the absorbed carotenoids. After having been fed on algae there is only a small amount of astacene (not astaxanthin!) in the strain from Canada. The metabolism of carotenoids in Artemia salina has been discussed.
Notizen: Über ein zellfreies System der Proteinsynthese aus Chlorella
Authors: Galling Gottfried
Published: February 2015

From cell homogenates of Chlorella pyrenoidosa, a system has been prepared which incorporates amino acids into acid-insoluble peptides. This system is dependent on energy regeneration (with phosphoenolpyruvate and pyruvate kinase), on GTP, and, to a lesser extent on CTP and UTP. Experiments with washed ribosomes show, a linear dependency of incorporation on ribosome concentration. By using a "pH-5-enzyme” preparation instead of the supernatant fraction, the incorporation can be stimulated by adding nucleic acids.
On the Mechanisms of Cytotoxicity by Cationic Tissue Proteins forCryptococcus Neoformans
Authors: Gadebusch Hans H.
Published: February 2015

A number of cationic constituents of mammalian tissue origin have been shown to possess potent in vitro anticryptococcal activity. Lysosomal cationic protein from rabbit leucocytes and plakin from human platelets altered membrane permeability resulting in release of ultra-violet-absorbing material from the cryptococci. In addition, oxygen uptake was significantly inhibited. Muramidase, the histones and, to a lesser extent, ribonuclease inhibited the uptake of radioactively-labelled amino acid
Über die Hemmung photosynthetischer Reaktionen isolierter Chloroplasten durch Chloroplasten-Antikörper
Authors: Berzborn R. , Menke W. , Trebst A. , Pistorius E.
Published: February 2015

The influence of two separated globuline fractions from rabbit antisera against isolated chloroplasts from Antirrhinum majus upon photosynthetic reactions of isolated chloroplasts from spinach has been investigated. The chloroplast antibodies had no effect on electron transport in a Hill reaction with ferricyanide, but one fraction inhibited noncyclic and cyclic ATP formation. This inhibition was reversed by preincubation of the antibody with coupling factor. Both globuline fractions inhibited photosynthetic NADP reduction; the inhibition of only one fraction was reversed by preincubation with ferredoxin-NADP-reductase. We conclude from these results that three components of photosynthetic activities are located on the surface of the thylakoids: the ATP forming system, the NADP-reductase, and an unknown factor participating in photosynthetic NADP reduction but not in ferricyanide reduction or cyclic electron transport
Über die ATPase von E. coli B 163 und seiner K-Mangelmutante B 525
Authors: Günther Th. , Dorn F.
Published: February 2015

Bei E. coli B 163 und seiner K-Mangelmutante B 525 untersuchten wir die Abhängigkeit der ATPase-Aktivität vom pH, von der Mg2 ⊕ - und von der Substratkonzentration sowie die Substrat- und Metallionenspezifität.

Die ATPase aus beiden Stämmen wird durch Na um 20% aktiviert. K und Strophanthin haben keine Wirkung. Durch Behandlung mit Desoxycholat wird die ATPase-Aktivität erhöht, die Aktivierbarkeit durch Na ändert sich dabei nicht.

Zwischen den ATPasen aus E. coli B 163 und B 525 bestehen keine Unterschiede
Stereospezifische Polymerisation von Propylenoxid mit Mn2(CO)10 nach UV-Bestrahlung
Authors: Strohmeier W. , Hartmann P.
Published: February 2015

Mangandecacarbonyl polymerisiert nach UV-Bestrahlung Propylenoxid stereospezifisch. Die Ausbeute an kristallinem isotaktischem Polypropylenoxid hängt nur von der Reaktionstemperatur ab und nimmt mit abnehmender Temperatur zu.

Im Gegensatz zu den anderen bisher bekannten stereospezifischen Katalysatoren wird mit Mn2 (CO) 10 als Katalysator ein isotaktisches Polymer einheitlicher Kristallinität erhalten.
Über die Rolle des Mg bei der Regulation des Zellstoffwechsels
Authors: Günther Th.
Published: February 2015

Mg2⊕ ist am Zustandekommen des Pasteur- und Crabtree- Effektes nicht beteiligt. Das ionisierte Mg2® in der Zelle ist auf einem Niveau gepuffert, bei dem die Mg-abhängigen Enzyme optimal oder nahezu optimal aktiviert sind.
Veränderungen der Hämolymphe vor der Verpuppung von Cerura vinula L.: Der Gehalt an Eiweiß, Aminosäuren, Ommochrom-Vorstufen und Ommochromen
Authors: Bückmann Detlef , Willig Axel , Linzen Bernt
Published: February 2015

Ommochrome synthesis at the beginning of lepidopteran metamorphosis is correlated to morpholytic and morphogenetic activity. In order to examine the metabolic alterations involved, data on respiration, haemolymph volume and on concentrations of total carbohydrate, soluble protein and non-protein nitrogen have been collected. Free aminoacids were separated by ion exchange chromatography and the levels of tryptophan, 3-hydroxy-kynurenine and of total ommochromes were determined independently at different stages during transformation of the larva towards the pupa. While the levels of non-protein nitrogen and of total free amino acids remain nearly constant, there is a three- and twentyfold increase of tryptophan and 3-hydroxy-kynurenine, respectively. It is proposed, that ommochrome formation serves in the removal of tryptophan liberated by proteolysis.
Die oxydative Phosphorylierung isolierter Leber- und Tumormitochondrien nach Zusatz von ᴅʟ- oder ᴅ(+)-Glycerinaldehyd
Authors: Wand H. , Bacigalupo G.
Published: February 2015

DL-Glycerinaldehyd wirkte auf isolierte Leber- und Tumormitochondrien von Ratten (Walker-Carcinosarkom 256) als starker Hemmer der Glutamatoxydation und der damit gekoppelten Phosphorylierung. Das Racemat verursachte demnach keine wesentliche Änderung der P/O-Quotienten sowohl von Leber- wie von Tumormitochondrien.

D(+) -Glycerinaldehyd setzte bei den Tumormitochondrien den Phosphatverbrauch stark herab, veränderte die Glutamatoxydation relativ wenig und erniedrigte den P/O-Quotienten deutlich; dagegen blieben Phosphatverbrauch und Glutamatoxydation der Lebermitochondrien unter dieser Einwirkung fast unverändert. D (+) -Glycerinaldehyd verhielt sich also in Gegenwart von Glutamat den Tumormitochondrien gegenüber ähnlich wie ein Entkoppler der oxydativen Phosphorylierung, ein Phänomen, das bei Einsatz von Lebermitochondrien nicht nachzuweisen war.

Die Succinatoxydation und der Phosphatverbrauch der Tumormitochondrien wurden durch ᴅ (+) -Glycerinaldehyd stärker erniedrigt, als dies bei Lebermitochondrien der Fall war. ᴅʟ-Glycerinaldehyd hemmte die Succinatoxydation und den Phosphatverbrauch sowohl von Leber- als auch von Tumormitochondrien in gleichem Maße ohne Senkung der P/O-Quotienten.

Die Einwirkung von DL- bzw. D (+) -Glycerinaldehyd auf Tumormitochondrien mit Pyruvat +Malat als Atmungssubstrate ergab eine beträchtliche Hemmung der mitochondrialen Oxydation und der Phosphorylierung ohne wesentliche Erniedrigung des P/O-Quotienten.

Die sogenannte spontane Schwellung von Lebermitochondrien wurde durch ᴅʟ- oder ᴅ(+)-Glycerinaldehyd nicht beeinflußt.
I. The Terpene Marrubiin
Authors: Breccia Alberto , Badiello Roberto
Published: February 2015

The biosynthesis of the diterpene marrubiin has been studied using some labelled possible precursors: [2-14C] mevalonate, [1-14C] acetate, [2-14C] acetate, [2-14C] pyruvate, [2,3-14C] succinate, [1,4-14C] succinate, [5-14C] ketoglutarate and [1,5-14C] citrate. Metabolism times of 24, 36, 48, 72 and 96 hours were used. The labelled compounds were supplied in solution to flowering white horehound (Marrubium vulgare L.), cut at the base of the stem.

The incorporation results indicate that marrubiin undergoes a rapid turnover with a biological half life of about 24 hours. The rate of up-take of 14C from the prcursors is in the following order: [2-14C] mevalonate, [2-14C] acetate, [1-14C] acetate, [2-14C] pyruvate and [2,3-14C] succinate. Incorporation of 14C from the other compounds is negligible. If [2-14C] mevalonate is used, labelled marrubiin is formed 10 - 100 times more active than with the other precursors.

The results suggest that all the precursors are degradated to acetic units through the Krebs cycle before their utilization, with the exception of mevalonate.

Some samples of marrubiin (I) have been degradated chemically to the corresponding ketoderivative (II), in order to determine the distribution of radioactivity between the decahydronaphthalenic and furanic parts. The results are in good agreement with the distribution of the radioactivity in the molecule, as expected from the terpenoid structure of marrubiin.
Der Einfluß von Protonendonatoren auf die polarographische Reduktion von Nitroverbindungen in methanolischen Lösungen
Authors: Jannakoudakis Dimitrios , Wildenau Alfons
Published: February 2015

Bei der polarographischen Reduktion aromatischer Nitroverbindungen in Methanol kann durch Zusatz organischer Säuren ein Teil der Reduktionsstufe zu positiveren Potentialen vorverlagert werden. Die Höhe dieser Vorstufe ist durch die Säurekonzentration begrenzt; ist letztere hinreichend groß, so findet eine Verschiebung der gesamten Stufe statt. Die Potentialdifferenz gegenüber der ohne Säurezusatz beobachteten Stufe ist um so größer, je stärker die Säure ist, und der Effekt wird daher als Reduktionserleichterung infolge erleichterter Protonenübertragung gedeutet. Säuren, deren pK-Wert in wäßrigen Lösungen größer als 7 ist, bewirken keine Vorverlagerung. Den gleichen Effekt wie ein Säurezusatz bewirkt auch eine im Molekül des Depolarisators enthaltene Carboxylgruppe.
NMR-Spektren der Alkylcycloheptatriene
Authors: Kessler Horst , Müller Eugen
Published: February 2015

Die NMR-Spektren von monosubstituierten Alkylcycloheptarienen werden diskutiert. An Hand der chemischen Verschiebung des CHR-Protons in 7-substituierten Cycloheptatrienen und durch die Kopplungskonstanten mit den olefinischen Nachbarprotonen wird eine bevorzugte äquatoriale Stellung des Substituenten (das Proton in 7-Stellung steht dann axial) wahrscheinlich gemacht.
Einfluß organischer Insektizide auf Enzyme
Authors: Wildbrett Gerhard , Kiermeier Friedrich , Lettenmayer Ludwig
Published: February 2015

Organophosphor-Verbindungen, vorwiegend insektizider Natur, wurden hinsichtlich ihres Verhaltens gegenüber Xanthindehydrase untersucht. Hierbei erwiesen sich Ester, die wie Parathion einen sauren Acylrest besitzen, als wirksame Inhibitoren, und zwar um so ausgeprägter, je kürzer die an das zentrale Phosphoratom gebundenen Alkoxygruppen sind. In reinen Enzymlösungen trat der Effekt stärker hervor als in Milch. Phosphorsäure-Ester hemmten stärker als Thionophosphorsäure-Ester. Es gelang, die Inaktivierung durch Dialyse des inhibierten Enzyms aufzuheben. Vermutlich findet daher lediglich eine Adsorption am Enzym, aber keine Alkylierung statt.
Isolierung von Elymoclavin-O-β-ᴅ-fruktosid aus Kulturen des Mutterkornpilzes
Authors: Floss H. G. , Günther H. , Mothes U. , Becker I.
Published: February 2015

Elymoclavine-O-β-ᴅ-fructoside, a new type of ergot alkaloid, has been isolated from cultures of the ergot strain SD 58. Evidence is presented suggesting that this alkaloid is formed from elymoclavine and the sucrose of the medium by the action of invertase present in the fungal mycelia.
Heat and Photochemical Inactivations of Taka-Amylase A and Mechanisms of Protection by Substrate
Authors: Tomita Giiti
Published: February 2015

The heat, ultraviolet and riboflavin-sensitized visible inactivations of taka-amylase A are strongly inhibited by the presence of its substrate. The stabilization of the secondary structure of enzyme protein by the conformation change due to the formation of enzyme-substrate and -product complexes is responsible for the protection of enzyme from the heat inactivation. The photoinactivations are brought about by the combined effects of heat and photochemical processes. The observed protections from photoinactivations are due to the inhibition effects of substrate and its decomposition products on both processes. The thermodynamic quantities determined for the inactivation reactions throw some light on the relationship between the heat and photochemical processes, and on the mechanisms of the protective action of substrate.
Enzymatische und nicht-enzymatische Darstellung von „Thiaminpyrophosphataktiviertem Glykolaldehyd“
Authors: Pohlandt F. , Kohlhaw G. , Holzer H.
Published: February 2015

1. A reaction mixture, made from pig heart pyruvate oxidase, hydroxypyruvate, thiamine pyrophosphate, and magnesium chloride, is described in which thiamine pyrophosphate is almost quantitatively converted into 2-(1,2-dihydroxyethyl)-thiamine pyrophosphate (thiamine pyrophosphate-activated glycolaldehyde). This product can be isolated by ion exchange chromatography.

2. 2-(1,2-dihydroxyethyl)-thiamine pyrophosphate can also be isolated from reaction mixtures of yeast transketolase with hydroxypyruvate, thiamine pyrophosphate, and magnesium chloride, but in very low yield.

3. From non-enzymatic reaction mixtures containing thiamine pyrophosphate and a great excess of glycolaldehyde, a compound could be isolated, the tested properties of which were found to be the same as those of enzymatically prepared 2-(1,2-dihydroxyethyl)-thiamine pyrophosphate.

4. 2-(1,2-dihydroxyethyl)-thiamine pyrophosphate gives rise to only 55% of the thiochrome which is produced from the same quantity of thiamine pyrophosphate. This behaviour can be used for the determination of relative concentrations of thiamine pyrophosphate and 2-(1,2-dihydroxyethyl)-thiamine pyrophosphate in mixtures.
Die Wirkung freier Phagenrezeptoren auf Proteus-Phagen in Gegenwart von Polykationen
Authors: Zickler Fritz
Published: February 2015

Die Phagen-Rezeptor-Reaktion wird durch Polykationen nur dann gehemmt, wenn die Ionenstärke des Polykations stärker oder ebenso stark ist wie die wirksame Bindungsgruppe im Phagen. Es wird angenommen, daß die in Phagen vorkommenden Spermidin- und Putreszinmoleküle neben ihrer Aufgabe bei der Knäulung der Phagen-DNS noch am Phagenbindungsmechanismus beteiligt sind.

Spermin beeinflußt nicht die Inaktivierung des Pm 2-Phagen durch spezifisches Antiserum.
Particular Activity of Naphthacene Derivatives as Inducers of Zoxazolamine Hydroxylase Synthesis in Rats
Authors: Buu-Ηοϊ N. P. , Hien Do-Phuoc
Published: February 2015

High activity as inducers of microsomal zoxazolamine hydroxylase synthesis in rats has been found to be remarkably frequent in derivatives of the linear tetracyclic hydrocarbon naphthacene and their heterocyclic structural analogues. The relationships between chemical structure and this type of biological activity, which is shown to be independent of carcinogenic properties, are discussed.
Darstellung und Struktur von Polyphosphorsäurephenyl-Estern
Authors: Schramm G. , Berger H.
Published: February 2015

Ethylpolyphosphates have been prepared by reacting P4O10 with either triethylorthophosphate or with ethylether. Phenylpolyphosphates were prepared from P4O10 and triphenylorthophosphate at 300 °C. By the same procedure, o-kresylpolyphosphates could also be obtained, but not p-nitro-phenylpolyphosphates.

The various polyphosphate esters were subjected to nuclear magnetic resonance analysis to characterize the distribution of phosphate moieties present, branching groups, middle groups, end groups, and orthophosphates. A true equilibrium between the units was found for ethylpolyphosphates and the systems could be accurately described by the theory of van Wazer. This theory does not seem to hold for the present results with polyphenylphosphates. However, the experimental data can be described quantitatively with a modified form of the theory.

Ethylpolyphosphates can either phosphorylate or alkylate nucleophilic groups and alkylation is favored by the presence of protons. Only phosphorylation is observed with phenylpolyphosphates.

Solvolysis of the polyphosphate esters with water or n-butanol leads to a very rapid disappearance of branching groups and a slow disappearance of the middle groups. The amount of reactive phosphorus can be calculated from the nuclear magnetic resonance data.

The application of phenylpolyphosphates for a number of synthetic procedures is discussed.
Hemmung der steroidabhängigen Enzyminduktion bei Pseudomonas testosteroni mit Alkaloiden
Authors: Maturová M. , Beckmann H. , Wacker A.
Published: February 2015

Induction of the enzyme Δ5-3-ketosteroid isomerase in Pseudomonas testosteroni was found to be strongly inhibited by reserpine and by the alkaloids of Vinca and Ergot. Morphine, colchicine and papaverine caused weaker inhibition whilst a series of other alkaloids were almost ineffective. Ergot alkaloids were inhibitory towards all steroids tested, androgens, oestrogens and progestagens, and a similar effect was shown with the other inducible enzymes, 3α- and 3β.17β-hydroxysteroid-dehydrogenase.

Experiments with cell-free protein synthesis indicate that reserpine inhibits the induction of messenger RNA.
Der Einfluß einer Röntgen-Ganzkörperbestrahlung auf den Einbau von 2-14C-Glycin in die Proteine der Leber, Milz und des Blutes von Ratten
Authors: Maass H. , Jenner E. , Hölzel F.
Published: February 2015

Whole body irradiation with 800 R caused a three fold increase of radioactivity in the liver and spleen proteins of rats. Analysis of the radioactivity of the precursor pool showed an increase of 14C-activity to the same degree as found for the proteins. Thus the increase of the incorporation rate of 14C-glycine into the proteins is simulated, and consequently there is no change of the protein synthesis in the liver of an irradiated rat as measured with 14C-glycine. This is probably true for the rat spleen also.
Embryonale Induktion und Hemmung der Ribonucleinsäure-Synthese durch Actinomycin D
Authors: Tiedemann Hildegard , Born Jochen , Tiedemann Heinz
Published: February 2015

Blastoporal lip (presumptive notochord and myotomes) together with adjacent ectoderm (which is induced to form the neural system by the blastoporal lip) from early gastrulae was explanted and treated with 0,5—2,5 µg/ml actinomycin D for periods ranging from two hours to several days. The RNA synthesis is completely inhibited at 2,5 μg/ml Actinomycin D and partially inhibited at 0,5 μg/ml actinomycin D. At 2,5 µg/ml some notochordal cells are still formed, but the differentiation of neural tissue is completely inhibited. At 0,5 μg/ml actinomycin D notochord and muscle are more resistent than the neural tissue.

The inducing capacity of the blastoporal lip is not diminished after treatment with actinomycin D. Actinomycin D must therefore impair the competence of the ectoderm to be induced by inhibiting the RNA synthesis.

If tissues from tailbuds, which are already differentiating into muscle, notochord and spinal cord are explanted and treated with actinomycin D the differentiation is partially inhibited, but a differential sensitivity of these tissues is not observed.

The overall rate of protein synthesis is somewhat enhanced after treatment with 0,5 μg/ml actinomycin D for 2 — 5 hours.
Messung der Kaliumisotopen-Verteilung an menschlichen und tierischen Zellen zum Studium des aktiven Transports
Authors: Zimmermann U. , Wagener K.
Published: February 2015

Die massenspektrometrische Messung des Kaliumisotopen-Verhältnisses K39/K41 im Zellwasser und extracellulären Medium bei Menschen- und Hühnerblut sowie Fl-Zellen ergab innerhalb der Fehlergrenze von ± 0,35% keine Verschiebung im Isotopenverhältnis.

In Anbetracht des großen Konzentrationsunterschiedes, den das Kalium zwischen beiden Phasen zeigt, ist diese auffällige Tatsache von Bedeutung bei der Klärung des aktiven Transportmechanismus.
31P-Kernresonanzspektren deuterierter Phosphorverbindungen
Authors: Fluck Ekkehard , Binder Herbert
Published: February 2015

Die generelle Struktur der Spektren deuterierter Phosphorverbindungen ist theoretisch abgeleitet und diskutiert. Die Spektren einer Reihe deuterierter Verbindungen mit Phosphor der Koordinatenzahl 4 sind durch ihre Daten charakterisiert und teilweise abgebildet.
Massenspektrometrische Untersuchung der Entgasungsprodukte von Wasserstoff-haltigen Al-Si-Legierungen
Authors: Wolf G. , Mannchen W.
Published: February 2015

Die Entgasungsprodukte von wasserstoffhaltigen Aluminium-Silicium-Legierungen werden massenspektrometrisch untersucht. Bei der durch Natriumzusatz veredelten Legierung wird das Auftreten von Siliciumsubhydriden beobachtet. Dies ist nicht der Fall bei der unveredelten Legierung.
Die Aminosäuresequenz des Asparaginsäure enthaltenden Mureins von Lactobacillus coryniformis und Lactobacillus cellobiosus
Authors: Plapp Roland , Kandler Otto
Published: February 2015

The amino acid sequence of the peptide moiety of the mureins of Lactobacillus coryniformis and Lactobacillus cellobiosus cell walls was determined. This was accomplished by the identification of peptides obtained after partial hydrolysis of purified cell walls and by the identification of UDP-activated murein precursors accumulated by ᴅ-cycloserine inhibition. The amino acid sequence proved to be : ʟ-ala-ᴅ-glu-ʟ-lys-ᴅ-ala for L. coryniformis and L-ala-D-glu-L-orn-D-ala for L. cellobio-.

D-asp D-asp

sus. Aspartic acid is involved in the cross-linking of the mureins by forming a peptide bond with the C-terminal D-alanine of an adjacent muropeptide. Glutamic acid as well as aspartic acid are present as amides.
Nucleinsäuren in Chloroplasten I. Charakterisierung der DNS und RNS von Antirrhinum majus
Authors: Ruppel Hans Georg
Published: February 2015

The occurrence of nucleic acids in chloroplast preparations and leaves of Antirrhinum majus has been investigated.

Chloroplast preparations isolated from freeze-dried leaves in a non-aqueous medium were found to contain DNA. Characterization of the DNA was based on chemical analyses and density gradient centrifugation. The chloroplast DNA has a density of 1.698 g/cm3 corresponding to a guaninecytosine content of 37 — 38%. The hyperchromic effect of the DNA has shown its double-stranded structure. Leaf DNA has also been characterized by density gradient centrifugation and shown to contain as major component the nuclear DNA with a density of 1.689 g/cm3 which corresponds to a guanine-cytosine content of about 31% and a minor component identified as chloroplast DNA.

Extraction of the total nucleic acids of chloroplast preparations and their chromatographic separation on methylated serum albumin column yielded 5 fractions as follows: Soluble RNA (fraction I) with s=3.8—4.0, DNA (fraction II) containing small but detectable amounts of an unknown RNA component, two RNA fractions presumable of ribosomal origin with s = 17 (fraction III) and s = 26 (fraction IV), and a RNA fraction heterogeneous in molecular size (fraction V) with s=23 — 50. The soluble RNA has a high GC-content whereas fraction V shows a relative high adenine content. Compared with the nucleic acids from leaves the chloroplast preparations contain the same fractions, differing only in the higher content of fraction III related to the amount of fraction IV. Beside the DNA fraction of leaf extract with the sedimentation coefficient of s = 12 — 13 a further UV-absorbing component with s=5.0—5.5 has been found. Its character is unknown.
Eine Porphinsynthese durch anodische Oxydation von Pyrrol in Anwesenheit von Aldehyden
Authors: Stanienda A.
Published: February 2015

Pyrrole has been oxidized in an irreversible wave on a rotating Pt-disc electrode in acetonitrile. When oxidation was carried out in the presence of benzaldehyde it was possible to isolate tetraphenylporphine. The porphine synthesis is initiated by protons formed on the oxidation of pyrrole. Addition and condensation of protonated pyrrole molecules with benzaldehyde formed tetraphenyl· porphinogen, which was oxidized to tetraphenylporphine anodically or by redox reaction in solution. This redox reaction with pyrrole forms dihydropyrrole which proceeds finally to chlorins and explain also the current yield greater than a hundred per cent. This synthesis of porphine can be achieved in a few minutes at -70 °C by addition of acid to a solution of pyrrole and benzaldehyde.
Über die Inhaltsstoffe einiger Stictaceen
Authors: Huneck Siegfried , Follmann Gerhard
Published: February 2015

Es wird die Isolierung und Charakterisierung der Inhaltsstoffe aus fünf chilenischen Pseudocyphellaria-Arten beschrieben. Pseudocyphellaria intricata (DEL.) WAIN. var. thouarsii (DEL.) WAIN. enthält 7ß-Acetoxy-22-hydroxyhopan (I) und 15ɑ-22-Dihydroxyhopan (II), Pseudocyphellaria durvillei (DEL.) WAIN. Pulvinsäurelacton (III), Calycin (IV), die beiden neuen Triterpene Durvillonol und Durvilldiol sowie eine nicht näher definierte Substanz vom Schmp. 98 — 99°, Pseudocyphellaria hirsuta (MONT.) MALME III, IV, Usninsäure, Ergosterin und D-Mannit, Pseudocyphellaria crocata (L.) WAIN. III, IV und ein phenolisches Produkt vom Schmp. 258—260° und Pseudocyphellaria aurata (ACH.) WAIN. III und IV.
Zur Strukturaufklärung des Additionsproduktes von Maleinsäureanhydrid an β-Naphthol
Authors: Naegele Walter , Wendisch Detlef
Published: February 2015

TAKEDA und KITAHONOKI 1 beschrieben die Addition von Maleinsäureanhydrid an β-Naphthol und machten vor allem durch IR-spektroskopische Untersuchungen eine bicyclische Struktur (I) für das Addukt wahrscheinlich.

Durch kernresonanzspektroskopische Untersuchungen konnten wir einen sicheren Strukturbeweis für das Additionsprodukt im Sinne von Struktur I erbringen.
Wachstumsgeschwindigkeit der Peptidkette im Tabakmosaikvirus
Authors: Diringer H. , Anderer F. A. , Schramm G.
Published: February 2015

The rate of incorporation of labelled amino acids into the complete tobacco mosaic virus (TMV), into soluble virus protein and into soluble cell proteins has been determined in discs of infected and healthy tobacco leaves. The rate of overall protein synthesis is increased by 50% in the infected leaves. At least 60% of the increase derives from the synthesis of virus-specific proteins and the synthesis of cellular proteins is not inhibited. The virus protein synthesis is strongly temperature dependent and shows a maximum at 28 °C.

The exchange of free labelled amino acids between the external medium and the inner cellular pool reaches equilibrium within ten minutes. The influence of the exchange rate on the measurement of the kinetics of peptide chain synthesis is discussed in detail.

Discs from infected leaves were incubated for short periods at low temperatures in media containing 3H-tyrosine or 3H-proline. Peptides isolated after 5 minutes incubation at 15 °C were found to be uniformly labelled with no apparent gradient of radioactivity from the N- to the C-terminus. The results indicate that the growth rate of the peptide chain at 15 °C is probably higher than 2 - 3 amino acids/sec and at 28 °C higher than 20 amino acids/sec. These values are higher than those for animal cells and similar to those for protein synthesis in Escherichia coli.

Comparison of the growth rate of TMV protein with rate of total protein synthesis and the number of ribosomes in the tobacco leaves indicate that only a small portion of the ribosomes takes part in cell protein synthesis.
Zur Wirkung von substituierten α-Liponsäuren auf die Lipoamidoxidoreduktase -Reaktion
Authors: Goedde H. W. , Schloot W. , Schmidt U. , Malone J.
Published: February 2015

The reactions of various recently synthesized analogous of α-lipoic acid (especially with fluoride as substituent) with lipoic acid dehydrogenase from pig heart muscle were investigated. The influence of structural change on the reactivity of the various compounds, when reacting with lipoic acid dehydrogenase are discussed.