bluuebunny/crossref_metadata_2025_split huggingface dataset:
Der Nucleinsäure-Stoffwechsel der Rattenmilz während der Synthese von Antikörpern gegen Brucella abortus
Authors: Kröger H. , Papanastasiu D. 
Published: February 2015

1. 3H-Thymidin und 3H-Cytidin werden sehr rasch in die DNS bzw. RNS der Rattenmilz eingebaut.
2. Während der Erstimmunisierung mit Brucella abortus ist der Nucleinsäure-Stoffwechsel in der Rattenmilz gesteigert; die DNS-Synthese nimmt wesentlich mehr zu als die der RNS.
3. Die Basen-Zusammensetzung der Kern-RNS wird durch Immunisierung leicht verändert.
4. Während der Zweitimmunisierung mit Brucella abortus ist der Nucleinsäure-Stoffwechsel in der Rattenmilz ebenfalls gesteigert; die RNS-Synthese erreicht das Maximum schneller, die DNS-Synthese langsamer als bei der Erstimmunisierung.
Micro Determination of Molybdenum (VI) with Phenylazoxine S Dye
Authors: Goyal S. S. , Tandon J. P. 
Published: February 2015

Micro determination of molybdenum (VI) with 7-phenylazo-8-hydroxyquinoline-5-sulphonic acid is described. Molybdenum (VI) forms yellow, water souble complex in the pH range 2.5 — 5.5. 1:1 (M:L) stoichiometry has been established by (i) JOB’s and (ii) molar ratio methods. The colour reaction is instantaneous and the colour intensity remains unchanged for about 24 hours. The Beer's law is obeyed from 0.2 to 8.0 ppm of molybdenum per ml. The molecular extinction coefficient of the complex has been found to be E400 mµ =1.38 × 104, giving Sandell's sensitivity coefficient 0.0069 μg of molybdenum per cm2.
The values of formation constant (log K) and free energy of formation (JF°) obtained by three methods are 5.40 ± 0.3. 5.20 ± 0.15, 5.62 ± 0.03 and (-7.50 ± 0.40, —7.22 ± 0.20, —7.80 ± 0.04 K.cals) respectively. The interference due to a number of anions and cations in the determination of molybdenum (VI) has also been studied.
Azoxine S dyes having the general formula:

(where R represents substituted benzene ring)
have been found to form yellow, water soluble complexes with a number of metal ions. The dyes have been mainly used as metal ion indicators in recent years 1—5. However, a few physico-chemical studies on the complexation reactions of these dyes have also been reported 7—9.
In the present investigations, a detailed study of molybdenum (VI) complex of the 7-phenylazo-8-hydroxy-quinoline-5-sulphonic acid has been carried out and it has been shown to form 1:1 complex in the pH range 2.5 to 5.5. The reaction is quite sensitive and can be used for the micro determination of molybdenum (VI).
Die Verteilung 51Cr-markierter Clostridien-Sporen in Tumor-tragenden Ratten
Authors: Wenzel Martin , Eissner Dagmar 
Published: February 2015

Tumorgewebe wird mangelhaft mit Sauerstoff versorgt. Bei der i. v. Injektion von anaerob auskeimenden Sporen von Clostridium butyricum finden daher die Sporen nur im Tumorgewebe einen geeigneten Nährboden.
Mit Hilfe Tumor-tragender Ratten wurde daher untersucht, ob bei der i. v. Injektion von 51Crmarkierten Sporen sich eine bevorzugte Sporen- und damit Aktivitätsanreicherung im Tumorgewebe im Vergleich zum Normalgewebe feststellen läßt. Entsprechende Verteilungsstudien wurden in vivo durch Szintigraphie und nach Töten der Versuchstiere durch Aktivitätsmessung in den einzelnen Organen ausgeführt.
Die Ergebnisse zeigen eine bevorzugte Aktivitätsanreicherung im RES. Der zentrale nekrotische Bereich der Tumoren besaß eine erhöhte spezifische Aktivität gegenüber den Tumorrandgebieten.
Acteosid und Neoacteosid; Zuckerester aus Syringa vulgaris (L.) 1, 2
Authors: Birkofer Leonhard , Kaiser Christelmargot , Thomas Ursula 
Published: February 2015

Aus den Blüten des weißen Flieders (Syringa vulgaris L.) gelang es, sechs Kaffoylglykosen zu isolieren, von denen Acteosid (1) und Neoacteosid (2) in kristalliner Form erhalten wurden. Die Strukturaufklärung von 1 und 2 erfolgte durch Permethylierung, saure und alkalische Hydrolyse sowie Heranziehung der NMR-, UV- und IR-Spektren.
1 erwies sich als (3.4-Dihydroxy-β-phenyläthyl) 0-α-L-rhamnopyranosyl (1 →· 3) -β-ᴅ- (4-O-kaffoyl) glucopyranosid und 2 als (3.4-Dihydroxy-β-phenyläthyl) O-α-L-rhamnopyranosyl (1 →· 3) -O- [β-ᴅ-glucopyranosyl (1 →· 6)] -β-ᴅ- (2-O-kaffoyl) -glucopyranosid.
Bei den übrigen vier Verbindungen konnte papierchromatographisch ermittelt werden, daß es sich bei allen um (3.4-Dihydroxy-β-phenyläthyl) -glucoside handelt, bei denen die Kaffeesäure ebenfalls esterartig an dieser Glucose sitzt. Sie unterscheiden sich durch die Art und Anzahl der anderen Zuckerkomponenten. Einer der weiteren Inhaltsstoffe des Flieders konnte als (4-Hydroxy-β-phenyläthyl) -β-D-glucopyranosid (3) identifiziert werden.
Messungen zur Manipulation der Glucose-abhängigen Tumorsäuerung in vivo
Authors: Rauen Hermann Matthias , Friedrich Michael , Norpoth Klaus 
Published: February 2015

On experimental rat tumors, preferentially on DS-Carcinosarcoma, special glass electrodes were used to measure and to register development of tissue-pH after injection of glucose into the rats.
On tumor surface pH-values were lowered more quickly and increased much faster as in tumor depth. The lowest registered pH was about 5,9.
High s. c. dosages of Insulin caused a marked decrease of pH-values for nearly one hour too. In metabole effective small tumors tumor acidity could be regulated satisfactory with administered glucose and insulin between pH 7,0 and 6,0.
Determination of lactate concentration in tumor tissue, surrounding the electrode, indicated a linear correlation between pH-value und lactate concentration in the range between pH 6,0 and 7,0. Regression coefficient comes to — 40,9 ± 2,2 ×10-3 mMol/g wet weight and pH-unit.
It is emphasized that according to the varying cell supply the compact tumor shows no homogeneity on pH-rates, acidification kinetics, and sensibility against acidotic cell lesion.
Results are criticized with reference to other publications and their significance for the theory of tumor lesion by alkylating agents is discussed.
Enzymatische Glucosylierung von pflanzlichen Sterinen
Authors: Kauss H. 
Published: February 2015

A particulate enzyme preparation from dark grown mung bean shoots incorporates the glucosyl unit from UDP- (14C) -glucose into lipophilic products. These were identified by thin layer chromatography as a mixture of β-sitosterylglucoside and stigmasteryl-glucoside (80%) as well as the acylated forms of these substances (20%). The reaction is almost linear with time up to 10 minutes, optimal at pH values between 6.3 and 6.6 and does not require divalent cations. The acceptor sterols were shown to be present in the particulate preparation; exogenous sterols do not seem to act as acceptors.
The same particulate enzyme preparation can also synthesize cellulose from UDPG 15 and lipid intermediates for its biosynthesis have been predicted 20. It appeared possible, therefore, that the sterylglucosides act as such intermediates. This, however, does not seem to be the case, since dilution of the UDP- (14C) -Glucose with unlabelled UDPG as well as its hydrolysis with phosphodiesterase within the course of an experiment demonstrates that the glucosyl units of the sterylglucosides show no turnover.
II. Mitt.: Auflösung der Chromoproteidfraktion aus Rattenleber-Ribosomen mit Hilfe der Polyacrylamidgel-Elektrophorese
Authors: Domschke Wolfram , Meyer-Bertenrath Jürgen G. 
Published: February 2015

After preparation of a coloured protein component containing iron from rat liver ribosomes 1 this fraction was submitted to detailed analysis by means of polyacrylamide gel electrophoresis. Thus it may be separated into one main and two secondary bands, which do not contain RNA detectable by methylene blue staining. The ferric content of all bands can be demonstrated by staining with 2,4-dinitroso-1,3-naphthalenediol 2. These bands are to be found in the large ribosomal subunits as well as in the small one in qualitative conformity, they differ, however, in their quantitative relations to each other depending on origin. LiCl-extraction as described for the preparation of ribosomal proteins causes dissociation of the chromoproteid fraction into six bands possessing lower molecular weights each than the original bands.
The chromoproteids, localized in the large ribosomal subunits on the one hand and in the small subunits on the other hand were prepared differentiatedly by gel filtration. Results show the chromoproteid represented in the 57-S-subunit on a bigger scale than the nucleoproteid part, on the contrary, the 29-S-subunit is constructed of RNA-containing material preferably.
Observations on the Thermochromism of Triphenylchloromethane
Authors: Simoni Rosa , Toschi Maria 
Published: February 2015

Es wurde die Thermochromie von Lösungen des Triphenylchlormethane in Dekalin im Temperaturbereich von 25° bis 150°C untersucht.
Polarisationmessungen zeigen keine Veränderung bis 110°C. Der Thermochromie ist die Bildung des Triphenylmethyl-Radikals, das sich in Anwesenheit von Luft zersetzt, zuzuschreiben. Die Reaktionsprodukte wurden identifiziert und das Reaktions-Schema angegeben.
Einfluß von 5-Azacytidin auf Reversion und UV-Sensibilität von Escherichia coli K12-Stämmen mit unterschiedlichen UVR-Genen / Influence of 5-Azacytidine on Reversion Rate and UV-Sensitivity of Escherichia coli K12 Strains with different UVR-Genes
Authors: Grunow R. , Geissler E. 
Published: February 2015

3 µg AC/ml cause an inhibition of cell division of E. coli K12 strains. This concentration is not mutagenic, because the reversion frequencies of the markers thr-, his- and arg- are not changed by AC treatment. However the reversion frequencies of thr- and arg- increased 1 to 4 orders of magnitude after UV irradiation, simultaneous treatment with AC and UV decreased these enlarged reversion rates at 1 exponent. The marker his- used in this experiments is not reverted by UV.
The UV-sensitivity of bacterial strains with different uvr-genes is studied. The results are discussed from the view point that the influence of AC caused an inhibition of protein synthesis, whereby phenotypic expression of UV induced DNA damage is delayed and the time for repair of DNA is enlarged.
Über die Verwendung von 86Rb als Indikator für Kalium, Untersuchungen am lichtgeförderten 42K/K- und 86Rb/Rb-Influx bei Elodea densa/ On the Application of 86Rb as a Tracer for Potassium, Measurements of the Lightdependent 42K/K- and 86Rb/Rb-Influx in Elodea densa
Authors: Jeschke Wolf Dietrich 
Published: February 2015

1. The light-dependent influx of K⊕ and of Rb⊕ into isolated leaves of Elodea densa was measured by using 42K⊕ and 86Rb⊕ as tracers.
2. If 86Rb was used as a tracer for K⊕ and then the K⊕ influx was determined from the specific activity σ86Rb/K an influx vK(86Rb) was obtained which was lower than the K(42K) influx (fig. 1). The ratio of vK(42K)/vK(86Rb) = SK,Rb increased with increasing [Rb⊕]0 and decreasing [K⊕]0 (figs. 1 and 7). The depression of vK(86Rb) as compared to vK(42K) was not a consequence of the competitive inhibition of K⊕ influx by Rb⊕ (cf. fig. 1).
3. As a working hypothesis it is proposed that 86Rb⊕ functions only as a tracer of Rb⊕ and that vK(84Rb) can be calculated from the parameters of the Rb (86Rb) influx and its competitive inhibition by K⊕.
4. By using the Michaelis - Menten - Kinetics a formula was derived for vK(86Rb), the Michaelis constant KmK(86
Rb), and for VmaxK(86
Rb). From these calculations it may be predicted a) that vK(86Rb) will show a Michaelis - Menten - Kinetic only if [Rb⊕] is kept constant at all K⊕ concentrations; b) that VmaxK(86
Rb) is independent of [Rb⊕] and not necessarily equal to VmaxK(42
K); and c) that KmK(86
Rb) is greater than KmK(42
K) and dependent on [Rb⊕].
5. In order to test the calculations the mutual competitive inhibition of K⊕ - and Rb⊕ -influx (figs. 2, 3) was measured. From the Michaelis - Menten - Parameters of the Rb (86Rb) influx and the inhibition constant KiK of potassium vK(86Rb) was calculated. The predictions mentioned above were verified. The calculated depression of vK(86Rb) as compared to vK(42K) corresponded satisfactorily to the experimental values (fig. 7).
6. The isotherms of K (42K) and of Rb (86Rb) influx were measured (fig. 4). In the range of low concentrations (system 1) VmaxK(42
K) greatly exceeded VmaxRb(86
Rb), the same was true of KmK(42
K) as compared to KmRb(86
Rb). Thus in system 1 the Rb⊕ influx proceeded with much greater affinity but lower capacity than the K⊕ influx. Thus, although with regard to competitive inhibition K⊕ and Rb⊕ seem to use the same transfort site the relative similarity of vK(42K) and vK(86Rb) must be termed rather incidental though predictable.
7. At higher concentrations (system 2) the influx of K⊕ and Rb⊕ was less different with respect to Km and Vmax (fig. 7), an observation which was confirmed by competitive inhibition on almost equal terms.
8. It must be stated that the value of 86Rb⊕ as a tracer instead of 42K⊕ is limited. However, the metabolic linkages of K⊕ influx can also be detected by the use of 86Rb⊕.
Untersuchungen an Crown-Gall
Authors: Beiderbeck Rolf 
Published: February 2015

Concentrations of 10 µg/ml rifampicin reduce the growth of Agrobacterium tumefaciens by more than 90%, concentrations of 100 µg/ml prevent tumor formation in Kalanchoë daigremontiana by the same bacteria.
A treatment with rifampicin does not irreversibly alter the bacteria; after removal of the drug bacterial propagation and the ability of tumor induction are restored.
0-24 h treatments of the plant wounds with rifampicin prior to infection prevent tumor formation completely.
Addition of rifampicin after infection inhibits tumor formation optimally if the drug is added only few hours after inoculation. 30 h after infection the bacteria-host-system is resistant against rifampicin.
100 μg/ml rifampicin do not influence the growth of already induced tumors.
Die Aminosäuresequenz des Serin und Asparaginsäure enthaltenden Mureins von Bifidobacterium bifidum Orla Jensen/ The amino acid sequence of the serin and aspartic acid containing mureins of Bifidobacterium bifidum ORLA JENSEN
Authors: Koch Dieter , Schleifer Karl Heinz , Kandler Otto 
Published: February 2015

Cell walls of Bifidobacterium bifidum var. pennsylvanicus were isolated. The polysaccharide consisted of glucose, galactose and rhamnose. Teichoic acid was not present. The murein (peptidoglycan) contained MurNAc, GlcNH2NAc, ᴅ-Glu, Ala. ʟ-Ser, ᴅ-Asp and L-Orn in a ratio of about 1 : 1 : 1 : 2 : 1 : 1 : 1. In one batch a high amount of ʟ-glutamic acid was found. It was not a constituent of the murein since it remained in the lysozyme insensitive residue.
The amino acid sequence of the murein was determined by analyzing the oligopeptides arising during partial acid hydrolysis. It was shown that the peptide subunits attached to the muramic acid are the same as in many other mureins: ʟ-Ala-ᴅ-Glu-ʟ-Orn-D-Ala. The interpeptide bridge consisted of β-ᴅ-aspartyl-ʟ-serine. Since about 35% of aspartic acid and 6% of ornithine are N-terminal in the cell wall, it was assumed that only 60% of the peptide subunits are cross-linked. 4 other strains of B. bifidum proved to contain the same type of murein. While all other strains of other species of Bifidobacterium investigated contained other types of murein, it seems likely that the Orn-Ser-Asp type of the murein is typical of B. bifidum.
Das Bürzeldrüsensekret der Reiherente (Aythya fuligula)
Authors: Jacob Jürgen , Zeman Alfred 
Published: February 2015

The acidic and alcoholic components of the uropygial gland wax from the tufted duck (Aythya fuligula) were investigated by a combination of GLC and mass spectrometry. Main components of the acidic part of the waxes are 2,4,6-trimethyl-nonanoic (39.0%) 2,4,6-trimethyl-octanoic (8.7%) and 2,6-dimethyl nonanoic acid (5.9%). Besides, 2,4,8-, 2,6,8-, and 2,6,10-trimethyl-substituted fatty acids occur. As minor components 2-methyl- and homologous series of 2,4-, 2,6-, 2,8-, and 2,10-dimethyl-substituted fatty acids could be detected.
Main components of the wax alcohols were n-hexadecanol and n-octadecanol. As minor components 2-, 6-, 10-, 12-, and 14-methyl-branched primary alkanols occur.
The tufted duck shows an uropygial gland wax which is typical for the 17th order of the natural system
2-Anilinothiophene als Entkoppler der oxydativen Phosphorylierung in Mitochondrien / 2-Anilinothiophenes, Uncouplers of Oxidative Phosphorylation in Mitochondria
Authors: Büchel K. H. , Schäfer G. 
Published: February 2015

A series of NH-acidic 2-anilino-3,5-dinitro-thiophenes (II), 2-anilino-3,4-dinitro-5-halo-thiophenes (VI), and some 3,5-dinitro-thienole-derivatives (IX, X) were synthesized. Compounds II and VI are potent uncouplers of oxidative phosphorylation in rat liver mitochondria. The most active comcounds yielded a 50% uncoupling at a concentration of 10-7 ᴍ.
With some of the 2-anilino-3,5-dinitro-5-halo-thiophenes (BDCT or DDCT), added to respiring liver mitochondria, a transitory uncoupling of energy-linked reactions could be observed which is comparable to the phosphorylating cycles produced by ADP. The mechanism of this effect is discussed
Localization of ferredoxin in the thylakoid membrane with immunological methods
Authors: Wyk Doris Hiedemann—Van , Kannangara C. Gamini 
Published: February 2015

Antibodies were prepared against ferredoxin isolated from spinach. These antibodies and those against TPN-ferredoxin-reductase, carboxydismutase and coupling factor were used to clarify the localization of these proteins in the thylakoid membrane. Chloroplast preparations obtained by different methods show not the same immunological reactions. Only lamellar systems suspended in the leaf homogenate are agglutinated by anti-ferredoxin. Washed lamellar systems show an agglutination with anti-ferredoxin only if ferredoxin is added. In certain preparations of lamellar systems the presence of ferredoxin inhibit the reaction of anti-TPN-ferredoxin-reductase with the lamellar system. Lamellar systems freed of coupling factor by EDTA treatment are agglutinated by anti-TPN-ferredoxin-reductase. Addition of coupling factor to the EDTA treated lamellar systems inhibit the agglutination but not the adsorption of TPN-ferredoxin-reductase antibodies. By the assumption that the inhibition of the agglutination by the TPN-ferredoxin-reductase antibodies is caused by sterical hindrance, these results indicate, that ferredoxin, coupling factor and TPN-ferredoxin-reductase are localized close to each other in the thylakoid membrane.
Lamellar systems suspended in leaf homogenate are agglutinated by anti-TPN-ferredoxin-reductase. That means, that to a certain extend the molecular structure of the thylakoid membrane changes with the kind of preparations employed.
On the Structure of Peuarenarine, a New Coumarin from Peucedanum Arenarium
Authors: Zheleva A. , Bubeva-Ivanova L. , Spassov S. L. 
Published: February 2015

Three new natural coumarin substances 1, 2 and 3 (derivatives of 2′,2′-dimethyl-3′,4′-dihydroxydihydropyrano-5′,6′:6,7-coumarin) were isolated from the roots and fruits of Peucedanum arenarium W.K.
On the basis of the spectral data from UV, IR, and NMR spectra of coumarin 1, named peuarenarine, it was assumed, that, it is an ester of 2′,2′-dimethyl-3′,4′-dihydroxy-dihydropyrano-5′,6′:6,7-coumarin and of angelic and 2,3-epoxy-2-methylbutyric acids.
Charakterisierung und Kinetik des in der Rattenplacenta vorkommenden mikrosomalen Enzyms, das den Wasserstoff-Transfer von Oestradiol auf Androstendion katalysiert / Characterization and Kinetics of the Microsomal Enzyme of Rat Placenta which Functions as a “Transhydrogenase” between Estradiol-17β and Androstenedione
Authors: Pollow Kunhard , Pollow Barbara 
Published: February 2015

The microsomal fraction of rat placenta contains a 17β-hydroxysteroid-oxidoreductase which transfers hydrogen from position 17 of estradiol to androstenedione. This hydrogen transfer is dependent on NAD, NADP as cofactor is without effect. The optimum pH is at 6,9. In the presence of NAD the Michaelis constant for estradiol is 4,17 · 10-5м at pH 7,4. In the presence of androstenedione in the incubation medium the Km-value for estradiol is decreased, which indicates an increased affinity for the enzyme. The temperature optimum of the enzyme is 38 °C. Addition of SH-blocking agents inhibited the enzyme activity. Zinc and magnesium ions had an inhibitory effect on the “transhydrogenase” and B-NADPT specifically labelled from [1-T]-glucose showed that the non-effect of NADP on transhydrogenation from estradiol to androstenedione resulting in reduction of position 17 is not due to different stereospecifity.
The results show a close relation between the oxidative metabolism of estradiol and the reduction of androstenedione, indicating that estradiol-17β, as the preferred hydrogen-donating substrate, is an essential component of the androstenedione-hydrogenating system in the microsomal fraction of rat placenta.
Zur Lokalisierung der Proteinsynthese bei der Entwicklung des Lamellarsystems ergrünender Etioplasten / Localization of Protein Synthesis During Development of the Lamellar System of Greening Etioplasts
Authors: Lürssen Klaus 
Published: February 2015

The stromata of etioplasts, greening etioplasts, and chloroplasts contain proteins which crossreact with proteins of the lamellar system of chloroplasts. It is shown that at least one cross-reacting protein is a water-soluble precursor of the lamellar system.
The water-insoluble fractions of the plastids were dissolved in buffer containing Na-benzene-dodecylsulfonate and analyzed by gel electrophoresis. The disc electrophoresis patterns of the prolamellar bodies of etioplasts showed 8 protein-containing bands of which 7 were also present in the preparations from greening etioplasts. The latter also yielded 5 new protein-containing bands. The lamellar system of chloroplasts showed only 8 bands which were identical with those of greening etioplasts, but it had only 3 bands in common with the prolamellar bodies of the etioplasts. Two of these proteins may be identical with antigens cross-reacting with stroma proteins.
Zum Einfluß verschieden substituierter s-Triazine auf Stoffwechselreaktionen der Grünalge Ankistrodesmus braunii / The Influence of Different s-Triazines on the Green Alga Ankistrodesmus braunii
Authors: Rau Iris , Grimme L. H. 
Published: February 2015

The effects of four different substituted s-Triazines (Ametryn, Atraton, Atrazin and Simazin) on growth, photosynthesis, respiration and photoreduction of the green alga Ankistrodesmus braunii were studied.
The pl50-values ( = neg. log. of that concentration which produces 50% inhibition) for these reactions suggest a specific blocking of the second light reaction only in the very low concentration range of 10-6-10-7м. The most effective substance is Ametryn (p50(O2) =7.1) and the least effective Simazin (5.4).
At higher concentrations there are inhibitions which seem to affect the electron transport rather than the photosystem I.
Kinetik der Reaktion von 2.4-Dinitrofluorbenzol mit Imidazol-, SH- und Imidazol-SH-Verbindungen / Kinetics of the Reaction of 2,4-dinitro-1-fluorobenzene with Imidazole-, SH- and Imidazole-SH-compounds
Authors: Voigt Renate , Wenck Helmut , Schneider Friedhelm 
Published: February 2015

First order rate constants of the reaction of a series of SH-, imidazole- and imidazole/SH-compounds with FDNB as well as their pH- and temperature dependence were determined. Some of the tested imidazole/SH-compounds exhibit a higher nucleophilic reactivity as is expected on the basis of their pKSH-values. This enhanced reactivity is caused by an activation of the SH-groups by a neighbouring imidazole residue. The pH-independent rate constants were calculated using the Lindley equation.
The kinetics of DNP-transfer from DNP-imidazole to SH-compounds were investigated. The pH-dependence of the reaction displays a maximum curve. Donor in this reaction is the DNP-imidazolecation and acceptor the thiolate anion.
The reaction rate of FDNB with imidazole derivatives is two to three orders of magnitude slower than with SH-compounds.
No inter- or intra-molecular transfer of the DNP-residue from sulfure to imidazole takes place.