Volume 33, Issue 9-10

In several series of 581 samples, Higher Fungi, especially from the Boletales and Gasteromy­cetes, were analyzed by atomic absorption spectroscopy on their content of the trace metal silver. The highest Ag-content was found in the Lycoperdales (max. 50 mg/kg dry matter) and in some species of the genus Boletus (max. 15 mg Ag/kg). The other fungi tested showed a mean silver content of 1 mg/kg or lower. The species with the highest amounts of the trace metal were found to enrich silver 300 fold compared to the substrate.

Original carbonaceous material of fossile carbon plants from the divisions of the Equisetophyta (Calamariaceae), Lycophyta (Lepidodendraceae, Sigillariaceae), Filicophyta (Filicatae), and Spermatophyta (Pteridospermatae, Cordaitidae) was analyzed by atomic absorption spectroscopy on its content of the trace metals vanadium and nickel. The average V-content was found to be 10 to 100 fold higher than that of the neighbouring coal beds or that of the embedding materials, while the Ni-concentrations were found to be almost in the same range. The highest contents of V and Ni were found in the Calamariaceae and in the Pteridospermatae. The V-and Ni-contents of the fossile carbon plants are compared to those of related recent plant genera (clubmosses, horse­ tails, ferns), which were analyzed by 46 representative samples. A possible biogenous enrichment of V and Ni in plants of the carbon age is discussed.

By nonenzymatic model reactions, the influence of vanadium (VO 2+ , VO 3 − ) and other metal ions (Al 3+ , Fe 2+ , Fe 3+ , Zn 2+ , Ni 2+ , Cr 3+ ) on the transamination of 4,5-dioxovaleric acid (DOVA) with ʟ-alanine (Ala) to δ -aminolevulinic acid (δ-ALA) and pyruvic acid (PA) with pyridoxal phosphate (PLP) is investigated. The examinations of the partial reactions show that VO 2+ , VO 3 − and Fe 2+ effectively enhance both conversions, while Ni 2+ only promotes the conversion of DOVA to δ -ALA with pyridoxamine phosphate (PMP). Besides Cr 3+ , which inhibits the transaminations, all other metals tried slightly enhance both reactions. The coupled transamination DOVA/Ala to δ-ALA/PA with PLP as a catalyst is performed at 40 °C , the extent of the reaction being judged by the amount of δ-ALA formed. Among all metal ions tested, VO 2+ and VO 3 − were found to be the most effective ones. Fe 2+ , Al 3+ and Fe 3+ also slightly enhance the reaction, but all other metals do not influence or inhibit the transamination. In presence of VO 2+ or VO 3 − ions, the optimum pH of the reaction shifts from pH 4 to pH 7.4. The positive influence of vanadium on δ-ALA transamination is discussed in connection with known structures of analogous Schiff base complexes with metal ions.

Simple methods are described for the preparation of trans-[1- 14 C]monounsaturated fatty acids and cis -[1- 14 C]monounsaturated fatty acids, each with a fairly uniform distribution of positional isomers, which can serve as mixed substrates in biochemical studies. Methyl trans- [1- 14 C] octadecenoates and methyl trans-[1- 14 C] eicosenoates are prepared by partial catalytic hydrogenation of methyl [1- 14 C] linolenate and methyl [1- 14 C] arachidonate, respectively, follow ed by argentation chromatography of the partially hydrogenated products. Methyl trans-[1- 14 C] octadecenoates and methyl trans-[1- 14 C] eicosenoates, thus obtained, yield the corresponding methyl cis-[1- 14 C] octadecenoates and methyl cis-[1- 14 C] eicosenoates, respectively, after trans-cis equilibration and argentation chromatography. Hydrolysis of each of these methyl esters yields the fatty acids.

Two tobacco cell lines resistant to p-fiuorophenylalanine (PFP) and one resistant to 5-methyltryptophan (5-MT) are compared with wild type cells in their ability to absorb amino acids from the medium. One p-fluorophenylalanine-resistant cell line shows greatly reduced uptake of all amino acids so is resistant to growth inhibition by other amino acid analogs. The impaired absorption is noted with amino acids, amino acid analogs and shikimate, but not with cinnamate, salicylate, nicotine, glucose, 3-O-methylglucose and palmitate. The phenylalanine transport system of the PFP-resistant cell line and the wild type both have K m values of 90 µᴍ, but have different V max values. Several analogs of phenylalanine and several neutral L-amino acids inhibit the phenylalanine transport system, while ʟ-aspartic acid, ʟ-arginine, ᴅ-phenylalanine or chlorogenic acid do not interfere with the ʟ-phenylalanine uptake. The results indicate the presence of more than one transport system for amino acid uptake. The lessened uptake of all amino acids, the specificity of the uptake systems and the unchanged binding let us conclude that a pleiotropic mutation or that some inhibitor causes the reduced uptake of all amino acids by the PFP-resistant cell line.

It is shown by competition experiments that tobacco cell lines have distinct transport systems for ʟ-amino acids. For all tested amino acids the Lineweaver-Burk plots were diphasic indicating the presence of more than one carrier for any one amino acid. Moreover distinct transport systems for neutral, acidic and basic amino acids were kinetically characterized. Based on competition experiments neutral amino acids were absorbed by all transport systems. Aspartic acid entered the cells via its own carrier and via the basic carrier while arginine was taken up only by the basic carrier. Neutral amino acids such as ʟ-leucine or ʟ-phenylalanine were taken up faster than acidic or basic amino acids.

[19- 3 H ] Strophanthidol, fed to leaves of whole plants of Convallaria majalis L., was translocated to the rhizomes and roots. Oxidation to [19- 3 H] strophanthidin took place in the leaves only. No labelled glycosides of strophanthidol and strophanthidin were found; thus, the aglycones are not precursors of the respective glycosides. It is assumed that the first glycosidation occurs at the C-21 level.

The two most important theories on the mode of action of carcinogenic hydrocarbons are juxtaposed by a new theory. This theory refers to ideas which have been discussed for a rather long time in silicose research and describes a mechanism whose principle will possibly be important for the specific effect of some pharmaceutica.

The digestion of ribonuclease A by proteinase K yielded one major degradation product only, which could not be distinguished from ribonuclease S by electrophoretical and immunological methods. This component (ribonuclease K) possessing full catalytic activity was characterized to be (1-20/211-124) ribonuclease A . Combined action of proteinase K and trypsin on ribonuclease A leads to a significant increase of the inactivation rate which may be useful in the isolation of mRNA from polysomes.

The effect of Mg 2+ on the light-dependent reduction of NADP by an artificial electron donor has been investigated with isolated broken chloroplasts. In both short and long wavelength actinic light, addition of the salt under most conditions stimulates the yield and the saturation rate. The magnitude of the stimulation is a function of pH. T he data indicate that previous interpretations of the Mg 2+ effect in this system invoking changes in the spill-over rate between the photo­ systems is no longer tenable. It is suggested that addition of the salt causes activation of inactive reaction centers.

Phosphoenolpyruvate carboxykinase (PEPCK) from Phycomyces blakesleeanus was partially purified by protamine sulfate precipitation, ammoniumsulfate precipitation, and diethylamino ethyl cellulose (DEAE) treatment. This preparation was employed for the characterization of the enzyme. The K m values for phosphoenolpyruvate (PEP) and ADP were determined as 1.6 and 0.42 mᴍ. The nucleotid specifity was demonstrated for ADP exclusively. The use of sulfuryl reagents showed the presence of thiol groups sensitive against p-hydroxymercuribenzoate but not effected by N-ethylmaleimide.

Composition and metabolism of carotenoids in Arctodiaptomus bacillifer taken from a mountain lake in the Alps have been studied. This copepode contains esters of astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dion) mainly. Besides β-carotene (β,β-carotene) and unesterified zeaxanthin (β,β-carotene-3,3′-diol), esters of hydroxyechinenone (3-hydroxy-β,β-caroten-4-one), adonixanthin (3,3′-dihydroxy-β,β-caroten-4-one), and zeaxanthin were found. The metabolism of carotenoids in Arctodiaptomus bacillifer and a possible way of astaxanthin biosynthesis have been discussed.

Peroxidases were shown to be responsible for the degradation of flavanones as occuring after application of these substrates to plant cell suspension cultures. - Comparative studies with various flavanones and horseradish peroxidase showed that only 4′-hydroxyflavanones will be catabolized peroxidatically. - Intensive analyses of naringenin (5,7,4′-trihydroxyflavanone) degradation by horseradish peroxidase revealed that very complex reactions with many catabolites are involved. Main degradative pathways comprise a) hydroxilation in the 3′-position, b) elimina­tion of ring B leading to chromones, c) cleavage reactions of the heterocylic ring resulting in phenolic catabolites from ring A and most important d) oxidative destruction of ring A leading to C 6 - C 3 -, C 6 - C 2 - and C 6 -C 1 - units from ring B. - The data are compared with the results of feeding experiments and are discussed with regard to their physiological significance.

During illumination infiltrated spinach leaf sections show after a short log a linearly increasing 14 C-incorporation into membrane lipids from H 14 CO 3 - . Isolated intact chloroplasts show this increase only for the neutral lipid fraction (NL). Glyco-and phospholipid accumulation declines in the light. In chloroplast suspensions the increase in content and also in its 14 C-incorporation rate of the NL fraction is accompanied 1. by a proportional decrease of CO 2 -fixation capacity, 2. by a decrease of the P/2 e-quotient. From 14 C-incorporation kinetics, this increase of neutral lipids in plastid suspensions even after short illumination periods appears to be a consequence of an inhibited glycolipid - and phospho­ lipid synthesis from diglycerides.

Treatment of microalgae (Bumilleriopsis) with paraquat (1,1-dimethyl-4,4-dipyridylium dichloride) under culture conditions in the light for 20 or 160 h leads to light-induced oxygen uptake and more or less severe chlorophyll bleaching, which is accompanied by formation of malondial-dehyde. The ratio of chlorophyll to packed chloroplast volume remains about the same as that of the control, presumably indicating destruction of membranes concurrently with pigments. Unre­lated to retardation of growth, degree of bleaching or to the formation of malondialdehyde quite a uniform degree of inactivation (≈ 50%) of partial redox reactions is observed in the region of photosystem II and I except for the terminal part of photosystem I (pigment 700 → NADP + ) . The action of paraquat in the cell centers primarily on the photosynthetic membrane system and redox chain.

1.4-benzoquinones have been tested for their inhibitory activity on photosynthetic NADP + reduction by chloroplasts. Benzoquinones with one or two branched alkyl side chains are inhibitors of electron flow. Inhibitory activity can be highly increased if one - and even more if two - halogen substitutents are introduced into the quinone moiety. Iodine substitution yields a better inhibitor than bromine than chlorine. A quantitative structure activity relationship according to a bilinear model, as developed by Kubinyi, with the lipophilicity as the only parameter could be established.

1. The effects of lyophilization and the extraction of ubiquinone-10 on the kinetics of electron transport in Rhodopseudomonas capsulata Ala pho + have been investigated. 2. Lyophilization reduced the amount of ferrocytochrome c 2 photo-oxidized on a microsecond time scale following a single excitation. 3. Lyophilization increased the reactivity of the electron transfer components with redox mediators, particularly N-methyl phenazonium methosulphate (PMS). At a concentration of 1 µᴍ , PMS accelerated reaction center re-reduction, ferricytochrome c 2 re-reduction and ferrocytochrome b 50 oxidation. The cytochrome c 2 re-reduction stimulated by PMS was antimycin A insensitive but the cytochrome b 50 oxidation was partially antim ycin sensitive. 4. Removal of 25- 30 molecules of ubiquinone 10 per reaction center removed a secondary acceptor pool, had very little effect on the kinetics of ferricytochrome b 50 reduction and ferricyto­ chrome c 2 re-reduction, but markedly inhibited ferrocytochrome b 50 oxidation. Ubiquinone extraction also caused an increased stimulation of ferrocytochrome b 50 oxidation by PMS. 5. The involvement of tightly bound ubiquinone in cytochrome b reduction and in the cytochrome b-c 2 oxido-reductase, and the role of semiquinone species is discussed.

The accumulation of esterfied chlorophyll a (Chl a) in etiolated bean leaves was determined during a dark period of 60 minutes after 1 minute irradiation with white light. The separation of the pigments esterified with geranylgeraniol (GG), dihydrogeranylgeraniol (DHGG), tetrahydrogeranylgeraniol (THGG) and phytol (P) was performed by HPLC. The last step for chlorophyll a biosynthesis is confirmed to be an esterification of chlorophyllide a to Chl GG followed by a stepwise hydrogenation of the pigment-bounded alcohols to Chl DHGG and Chl THGG and finally to Chl a.

The change in internal pH in chromatophores from Rps. sphaeroides following short flash ex­citation has been investigated using the method of the fluorescence quenching of 9-aminoacridine. (1) A single turnover flash induced a fluorescence quenching of ≅ 0.4%. The fluorescence quenching was stimulated by valinomycin, and oligomycin, and inhibited by antimycin A. (2) The extent of the pH gradient generated by a single turnover flash at the external pH ≅ 8 was estimated to be less than 0.4 unit. (3) In a multiflash experiment the change in internal pH induced by each flash was found to be not linearly dependent on the number of protons which had been taken up after each flash from the external medium. We discuss the significance of the results with respect to the mechanism of phosphorylation. The release of H + taken up outside the chromatophore into the membrane could not be excluded by the present results.

From stroma-freed chloroplasts of Antirrhinum majus polypeptides with the apparent molecular weights 44 000, 26 000 and 20 000 were isolated. The antiserum to a polypeptide with the moleculair weight 44 000 inhibits the photoreduction of anthraquinone-2-sulfonate with dichlorophenol indophenol/ascorbate when the concentration of the electron donor dichlorophenol indophenol is low. The antiserum enhances the rate of phenazine methosulfate-mediated cyclic photophosphorylation. The variable fluorescence yield is increased by the antiserum . It is assumed that this polypeptide plays a role in electron transport between the two photosystems. From two polypeptides with the apparent molecular weight 26 000 one seems to belong to the reaction center of photosystem II as it inhibits the photooxidation of tetramethyl benzidine and diphenyl carbazide with suitable electron acceptors and inhibits electron transport between water and silicomolybdate. Variable fluorescence is not or not too strong decreased by the antiserum . The other polypeptide of the apparent molecular weight 26 000 inhibits the photoreduction of anthraquinone-2-sulfonate with high concentrations of dichlorophenol indophenol as the electron donor. Phenazine methosulfate-mediated cyclic photophosphorylation is also inhibited by the antiserum . Therefore, we should like to associate it with the reaction center of photosystem I. The antiserum to the polypeptide with the apparent molecular weight 20 000 inhibits the photoreduction of anthraquinone-2-sulfonate with low and high concentrations of the electron donor dichlorophenol indophenol. It enhances phenazine methosulfate-mediated cyclic photophosphorylation. The polypeptide, therefore, should be functionally involved on the acceptor side of photosystem I. The results obtained up-to-now on the function and localization of the polypeptides in the thylakoid membrane are summarized.

The maximal binding of antibodies to ferredoxin-NADP + -reductase, cytochrome f, plastocyanin, coupling factor of photophosphorylation, carboxydismutase and to a polypeptide with the apparent molecular weight 24 000 onto stroma-freed chloroplasts of Antirrhinum majus was determined. The three proteins involved in photosynthetic electron transport bind approximately 0.05 to 0.07 g antibodies per g chloroplasts. The chloroplast preparation itself binds maximally about 1 gantibodies. From an antiserum to carboxydismutase and to a membrane polypeptide with the apparent molecular weight 24 000 approximately double the amount of antibodies namely 0.1 to 0.14 g antibodies per g chloroplasts are bound. Extraction of stroma-freed chloroplasts with 0.02 ᴍ Tris buffer pH 7.8 containing 0.7 mᴍ EDTA caused a threefold increase of the amount of bound anti­ bodies in the case of the membrane protein. 40% of the amount of antibodies which can be maxi­mally bound by this chloroplast preparation is adsorbed out of an antiserum to the coupling factor. Out of an antiserum which contains equal concentrations of antibodies to ferredoxin-NADP + -reductase, cytochrome f and plastocyanin the same amount of antibodies is bound as out of an antiserum directed to only one of these components. This shows that the proteins involved in electron transport are located in a very close relationship to each other in the outer surface of the thylakoid membrane.

Asymmetric and symmetric bilayer membrane were formed from monolayers of egg lecithin and various retinal isomers. Capacitance of the asymmetric all-trans retinal/lecithin bilayer is 1.2 ± 0.1 µF/cm 2 . Asymmetrically formed membranes of 13-cis retinal/lecithin and 9-cis retinal lecithin were found to be 0.83 ± 0.06 and 0.56 ± 0.05 µF/cm 2 , respectively. Formation of bilayers of the various cis isomers appears to require the presence of solvent. Irradiation of the various retinal/lecithin films, under the proper conditions, leads to bilayers with marked changes in capacitance and conductance.

The cell surface areas of 3T3 and SV40-3T3 cells both for suspended and for flat cells growing on the culture substrate have been determined in dependence on growth density. The surface areas of flat 3T3 and SV40-3T3 cells turn out to be independent of growth density over a wide range. For 3T3 cells the surface area of flat cells com pares well with that determined by Collard and Temmink for suspended 3T3 cells taking the surface area of their coverlayer of microvilli into account. This indicates that upon suspension of flat 3T3 cells the surplus surface area is disposed of in the form of microvilli. For SV40-3T3 cells we obtained a surface area of flat cells which differs by a factor of about two from that of suspended cells as determined by Collard and Temmink including the surface area of microvilli. Microscopical diameters and electrical (“Coulter”) volumina of suspended 3T3 and SV40-3T3 cells depend only little on cell density in the range investigated.

Reproductive behaviour was studied in 192 gynandromorphs with female genitalia and reproductive system, produced by ring-X chromosome loss. Male and female behaviour patterns were frequently found to coexist in the same individuals, and male courtship behaviour, when it occurred, retained its characteristic hierarchical organisation. Sexually receptive individuals were found to be an almost perfect subset of those ovipositing, and the control of both of these behaviours mapped to the head, as did male orientation (courtship). High rates of wing flicking, a response of males to courtship, mapped rather to the thorax, although a quantitative analysis demonstrated that the frequency of flicking behaviour was also influenced by male tissue in the head. In non-ovipositing individuals mature oocytes were retained in the ovary. An egg held in the uterus is not deposited by a fly without female tissue in the head and all but one sexually receptive individuals laid eggs. It is therefore concluded that both of these behaviours depend upon closely related neural circuitry operating the genital musculature under control from the brain.

Given a large population with mixed random mating and selfing (one locus-two alleles) different models of frequency-dependent selection were discussed - including a simple biometrical model for considering and analysing the competitive effects between neighbouring individuals in plant populations. For each model there were studied: changes in gene frequencies, population genetic equilibria, times until reaching these equilibria etc. - in dependence of the different parameters used: composition of the initial population, probability of selfing, selection-coefficients, competition-parameters. Apart from only few differing results it follows from the studies performed in these investigations, that the different composition of the initial population is of no particular importance as well for the gene frequencies p̂ at equilibrium as for the time t̂ until reaching these equilibria. This result is especially right for p̂. Different probabilities of selfing and different degrees of dominance in the selection coefficients are indeed of some influence on the existence and location of the population genetic equilibria, but here too we find an disproportionately stronger dependence with the time t̂ until reaching the equilibrium than with the gene frequency p̂ at equilibrium . The special importance of overdominance for the maintenance of genetic polymorphisms, which is well known in the case of non­ frequency-dependent selection (see: model 1 of the present studies) turn out to be of some other meaning in the models of frequency-dependent selection, which were analysed in the present paper: Depart from only few special situations (model 2 ; complete self-fertilization in models 5 and 6 ; extremely high probabilities of selfing in model 7) nontrivial equilibria are reached for all degrees of dominance. Therefore, the special importance of overdominance mentioned above, not proves right in the case of frequency-dependent selection. The investigations of the present paper have shown, that existence and location of the non­ trivial population genetic equilibria are determined not so much by degree of dominance and probability of selfing, but the equilibria are mainly determined by the model of the investigation used in the concerning studies. In the case of frequency-dependent selection, therefore, the explicit form of the fitness values as functions of the frequencies plays the decisive role in maintaining genetic polymorphisms.

Exposite produce chemiluminescence when heated to 50 - 70 °C or treated with nucleophilic substances at room temperature. Initiation by Piperidine in Dimethylsulfoxide allows to determine 5 nmol of Phenyloxirane in 5 ml samples.

A hitherto unknown chalkon (2′-hydroxy-4′,6′-dimethoxy-chalkon-4-glucoside) of European mistletoe (Viscum album L.) has been isolated and identified.

Terpenic constituents of 23 species of subgenus Heterotropa growing in Japan were analyzed by means of gaschromatograph-mass spectrometer. Thirteen sesquiterpenes were identified from the essential oils together with fourteen monoterpenes. It is found that all species of Heterotropa contain considerable amount of mono- and sesqui-terpenes in the oils.

Nine flavonoids were isolated from leaves of Pinus jef­freyi and identified as kaempferol, the 3-glucosides of kaempferol, quercetin, isorhamnetin, laricitrin and syringetin, a 3-glucoside of an A-ring methylated kaempferol derivative, kaempferol-3-(p-coumarylglucoside) and kaempferol-3-(ferulylglucoside). Myricetin-3-rhamnoside was found dur­ing an earlier investigation.

Eleven flavonoids, four phenolic glucosides and one sugar ester were isolated from needles of Larix decidua and identified as: kaempferol, its 3-arabinoside and 3-rutino-side, quercetin-3-arabinoside, isorhamnetin-3-arabinoside and 3-(p-coumarylglucoside), laricitrin-3-glucoside and -3-rutino-side, myricetin-3-glucoside, syringetin-3-glucoside and apigenin-7-glucoside; the β-glucosides of p-hydroxybenzoic acid, vanillic acid, p-coumaric acid and ferulic acid, and the glucose ester of vanillic acid.

Dichloroacetaldehyde, a presumed metabolite of the in­ secticides dichlorvos and tridilorphon, is mutagenic in the Salmonella/microsome test. Its mutagenic potency is higher than that of the established mutagen dichlorvos. It is pos sible that the bacterical mutagenicity test only or mainly detects the effect of methylation by dichlorvos.

The cell-free extracts of peel, root, or callus tissues of citrus catalyzed the stepwise O-methylation of quercetin to rhamnetin, isorhamnetin and rhamnazin. Both rhamnetin and isorhamnetin were further methylated to rhamnazin and possibly to a trimethyl ether derivative of quercetin. The results seem to indicate the existence of both meta and para directing enzymes that are involved in the biosynthesis of methylated flavonoids in citrus tissues.

Phototrophic growth of Chromatium vinosum strain D on pyruvate or malate, and of Thiocapsa roseopersicina strain 6311 on malate or sulfide as sole electron donors was promotedby 5 mᴍ ʟ-ascorbate, while growth of T. roseopersicina on fructose was inhibited. Slow growth was obtained also with ascorbate alone. In ascorbate-containing cultures the medium developed a yellow to red-brown colour which showed an absorption maximum at 310 -320 nm. As colourless products of ʟ-ascorbic acid degradation by the two strains examined erythroascorbic acid and 2,3-enediol pentonic acid were found in cell-free culture filtrates by gas chromatographic analysis of the silylated residues and identified by their mass, IR and UV spectra.

14 C-labelled 3,4-dihydroxyphenylalanine (DOPA) was fed to the fruit bodies of Amanita pantherina. About 0.02% of radioactivity was incorporated into stizolobic and stizolobinic acids after 24 hours of the incubation. Radioactive stizolobic acid was crystallized after the addition of the authentic unlabelled material and the specific radioactivity was shown to be constant after repeated recrystallization. These results indicate that DOPA is metabolically active as a precursor of stizolobic and stizolobinic acids in A. pantherina, as in Stizolobiu mhassjoo.

Physical measurements were made on the ζ-aminolevulinic acid synthetase from Rhodopseudomonassph eroides. These include a Stokes radius of 3.8 nm, determined by gel filtration, and sedimentation coefficient of 5.46 S by sucrose density gradient centrifugation. From these measurements and the value of partial specific volume of 0.732 ml/g deter­mined from the amino acid composition, the following physical constants were calculated: molecular weight, 88000; diffusion coefficient, 5.65 × 10 -7 cm 2 s -1 ; frictional ratio, 1.30; axial ratio, 5.0. The enzyme is inhibited by more than 50% by glyceraldehyde 3-phosphate (1 mᴍ) , pyruvate (0 .02 ᴍ) , α-ketoglutarate (0.02 ᴍ) , urea (0 .8 ᴍ) , CoCl 2 (0.2 mᴍ) and hemin (5 µᴍ). The effect of these inhibitors on the possible regulation of this enzymic activity is discussed.

The 14 C labelled inactive protein obtained by sodium borohydride reduction of the enzyme, porphobilinogen synthase of Rhodopseudomonas spheroides, in the presence of [4- 14 C] 5-aminolevulinic acid, gave on acid hydrolysis and subsequent electrophoresis or two-dimensional chromatography a major radioactive spot which was confirmed to be N -ε-[4-(-5aminovaleric acid)] lysine (ALA-lysine) by comparing its co-chromatographic and electrophoretic be ­ haviour with the chemically synthesized ALA-lysine. An ε-NH, group of lysine residue of porphobilinogen synthase, is thus the binding site of the substrate, 5-aminolevulinic acid.

c-AMP(10 −4 ᴍ) has a stimulating effect on the growth of corn coleoptiles similar to that of IAA(10 -5 ᴍ) . However this effect of c-AMP is more rapid and ceases after ca. 3 hours. In the presence of the phosphodiesteraseinhibitor theophylline the stimulating effect of c-AMP lasts for 3,5 hours only, and after this period, the coleoptiles shrink and diminish in length.

The thiol groups of human blood serum proteins were determined after 24 hours interaction with dithionitrobenzoicacid (DTNB) to an average of 538 ± 60 µmol/l serum. After treatment of the serum with [ 35 S]DTNB , autoradiograms of the protein elpherograms revealed two main peaks: The first with 63% of total activity, in the albumin region, corresponding to 0.60 SH/mol, the second with 23% of total activity, in the 7-globulin range, corresponding to 2.2 SH/mol. After 30 minutes incubation with D TNB , or with p-chloromercuribenzoate (CMB), in freshly prepared pools of IgG only 0.2 SH/mol were found which is the expected value already known from the literature. Autoradiograms taken from serum protein elpherograms after interaction with [UC] CMB only show the main SH-peak in the albumin range. Thus ist is concluded that the SH-peak in the γ-globulin region after 24 hours incubation with [ 35 S]DTNB is due to one highly labile S-S-bond which easily undergoes a disulfide exchange with DTNB .