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1.
- In the early stage of CO2-fixation by Thiobacillus thiooxidans,which was incubated aerobically in the presence of sulfur, mostpart of the fixed carbon was found in the phosphate ester fraction.
- The fixation was inhibited by NaF, picolinic acid, PCMB, azide,dipyridyl, o-phenanthroline, monoiodoacetic acid, and arsenite,each in the concentration range where the sulfur oxidation wasnot affected strongly.
- The crude extract of this organismcould fix CO2 in the presenceof ATP, R-5-P and Mg++. Most partof the fixed carbon was foundin PGA.
- The crude extract showedthe CO2-fixation coupled with the H2S-oxidationin the presenceof ADP.
- An appreciable reduction of PGA could not be detectedin thepresence of reducing systems, involving TPNH and DPNH.
2.
- From a strain of Acetobacter suboxydans, a glucose and a lacticenzyme were obtained in cell-free states. The lactic enzymeshows as strong activity as the glucose enzyme but is more stablethan the latter toward various purification procedures: bothare sensitive to high temperature treatment. Activities of thetwo enzymes and the MICHAELIS constants of the glucose enzymewere determined under both aerobic and anaerobic conditions.
- Carbon monoxide inhibits the oxygen-uptake in both glucoseandlactate oxidation. WARBURG's distribution constant for lactateoxidation is 6.7. These results suggest the participation ofan heme enzyme in the oxidation system.
- Effects of copperreagents, narcotics and PCMB were also examined.
- The dehydrogenaseactivities (reduction of dye) of the enzymesare more sensitiveto high temperature than the correspondingactivities in oxygen-uptake.
- By combining a dehydrogenase preparation which has lost itsoxygen-absorbing activity through acetone treatment, with aheated extract, a partial recovery of oxygen-uptake can be realizedin lactate oxidation.
- L-Cysteine is utilized as hydrogen donorby the bacterium. Thisoxidative reaction, unlike the oxidationof lactate, is notinhibited by surface active reagents.
3.
- Menadione (vitamin K3) was found to be completely reduced byilluminated spinach chloroplasts under highly anaerobic conditionand in the presence of ethylenediamine tetraacetate (EDTA) inthe reaction mixture. This photoreductive reaction is sensitivetoward heat-treatment and inhibited by 2?10-3M hydroxylamine.
- In the presence of oxygen, the reduced form of menadione israpidly photooxidized by chloroplasts. This photooxidative activityalso is suppressed by heat-treatment but not inhibited by hydroxylamine.
- Dyes which are inefficient as HILL oxidants such as thionineand methylene blue were found to be readily reduced by illuminatedchloroplasts, if the experimental conditions were appropriateto prevent the reoxidation of the photoreduced dyes; i.e., exhaustiveremoval of oxygen and the addition of EDTA in the reaction mixture.Menadione was found to accelerate the HILL reaction with thesedyes as oxidant under such experimental conditions.
- In thepresence of molecular oxygen in the reaction mixture,menadionewas found to inhibit the HILL reaction with 2,6dichlorophenolindophenol as oxidant, while the reaction rate was little influencedin high anaerobiosis.
- These findings are explained by theintermediary oxidation and(photo-) reduction of menadione asan intermediary hydrogencarrier, and by the trends toward rapidphotooxidation of reducedmenadione.
4.
Metabolism of some sulfur-containing substances was studiedin a copper-resistant strain of yeast (R), its parent strain(P) and respiratory-deficient(RD) mutants from them. The resultsobtained are as follows:
- Using sulfate, sulfite and thiosulfate as sulfur sources, Rproducedmore H2S than P, and both of these had the activityhigher than their RD mutants. All of them produced a large amountof H2S from cysteine, but only little from methionine, cysteinesulfinic acid and S-sulfocysteine.
- From sulfite and thiosulfate,P and R produced more H2S inaerobicthan in anaerobic condition.With sulfate and cysteine, however,H2S production did not differunder those conditions.
- In both P and R, the sulfate-to-sulfiteand sulfite-to-sulfidereactions were remarkably lowered byiron and zinc deficiencies.But the cysteine-to-sulfide reactionwas not affected by themetal-deficiencies.
- H2S productionfrom sulfate was remarkably depressed by highconcentrationsof pantothenate.
- Rates of reaction steps on a plausible pathway from sulfatetosulfide and to organic sulfur compounds areestimated forthe strainsused. R is characterized by its largecapacity ofthe reaction step from sulfate to sulfite, and excessivesulfitethus formed is liberatedas sulfide not by the way ofcysteine.
5.
Properties of the oxidation systems of sulfur and sulfite ofa sulfur oxidizing bacterium, Thiobacillus thiooxidans, arecompared by using various inhibitors. Oxidation of sulfur isinhibited by a low concentration of monoiodoacetic acid, NEMand pCMB. Inhibition by pCMB is diminished by the addition ofan equivalent amount of cysteine to that of added pCMB. Althoughinhibition by pCMB is also observed in the oxidation of sulfite,it is not diminished by the addition of excess cysteine andthe extent of inhibition is lower than that in the oxidationof sulfur. Metal chelating agents, such as DDC, 8-hydroxyquinoline, salicylaldoximeand neocuproine have inhibitory effects on the oxidation ofsulfur but do not affect the oxidation of sulfite. Carbon monoxide inhibits the oxidation of sulfur photo-irreversiblyand the oxidation of sulfite photo-reversibly. Alcohols and organic acids, inhibit the oxidation of both sulfurand sulfite. The cell-free extract prepared by sonic disruptionof cells can oxidize sulfite, but not sulfur. The sulfur oxidizingextract can be, however, prepared by disruption under a nitrogenatmosphere. Both the soluble and participate fractions are requiredfor the oxidation of sulfur, while sulfite oxidation is catalyzedby the participate fraction alone.
1Partly supported by a grant from the Ministry of Education. 相似文献
6.
- Two forms of enzyme capable of catalyzing the oxidation of L-glutamate(and L-aspartate) were isolated from the leaves of spinach andseparated from each other by column-chromatographic purificationon calcium phosphate and anion exchangers. They were distinguishedas GD1 (L-glutamate dehydrogenase 1) and GD2 (L-glutamate dehydrogenase2). The purification procedures and some fundamental propertiesof the partially purified enzymes were investigated.
- It wasdiscovered that the enzymes did not require any cofactor,ie., neither dialysis nor precipitation with ammonium sulfatecaused a fall in enzyme activities and the addition of DPN andTPN to the reaction mixture did not accelerate the reactionrate
- From the results of spectroscopic investigation GD1 andGD2were shown to be flavoproteins, although their prostheticgrouphas not yet been identified The activity of GD1 was enhancedby the addition of FAD or FMN, while GD2 was not acceleratedby these factors.
- The characteristics of the two enzymes includingsubstrate specificity,MICHAELIS constant, optimum pH of thereaction and specificityfor electron acceptors were compared.
- From the stoichiometric study of the oxidation of L-glutamatewith these enzymes, it was confirmed that the reaction is representedby the following equation: L-glutamate+oxidized dye+h2o
- Among various inhibitors tested,molecular oxygen which couldfunction as electron acceptor ofL-glutamate oxidation in thepresence of GD1 was found to causea strong inhibition uponthe same reaction with TTC as el acceptor.The inhibition wasconfirmed to be due to hydrogen peroxideproduced as a resultof the aerobic oxidation of L-glutamate.
7.
Robert L. Starkey 《The Journal of general physiology》1935,18(3):325-349
Various cultures (previously described), which oxidize thiosulfate in mineral media have been studied in an attempt to determine the products of oxidation. The transformation of sodium thiosulfate by Cultures B, T, and K yields sodium tetrathionate and sodium hydroxide; secondary chemical reactions result in the accumulation of some tri- and pentathionates, sulfate, and elemental sulfur. As a result of the initial reaction, the pH increases; the secondary reactions cause a drop in pH after this initial rise. The primary reaction yields much less energy than the reactions effected by autotrophic bacteria. No significant amounts of assimilated organic carbon were detected in media supporting representatives of these cultures. It is concluded that they are heterotrophic bacteria. Th. novellus oxidizes sodium thiosulfate to sodium sulfate and sulfuric acid; the pH drops progressively with growth and oxidation. Carbon assimilation typical of autotrophic bacteria was detected; the ratio of sulfate-sulfur formed to carbon assimilated was 56:1. It is calculated that 5.1 per cent of the energy yielded by the oxidation of thiosulfate is accounted for in the organic cell substance synthesized from inorganic materials. This organism is a facultative autotroph. The products of oxidation of sodium thiosulfate by Th. thioparus are sodium sulfate, sulfuric acid, and elemental sulfur; the ratio of sulfate sulfur to elemental sulfur is 3 to 2. The pH decreases during growth and oxidation. The elemental sulfur is produced by the primary reaction and is not a product of secondary chemical changes. The bacterium synthesizes organic compounds from mineral substances during growth. The ratio of thiosulfate-sulfur oxidized to carbon assimilated was 125:1, with 4.7 per cent of the energy of oxidation recovered as organic cell substance. This bacterium is a strict autotroph. 相似文献
8.
- Several kinds of a-hydroxysulfonates, the bisulfite additioncompounds of aldehydes and ketones, were found to inhibit thephotosynthetic carbon dioxide fixation of the barley and wheatseedlings, tobacco leaf and Chlorella cells. Bisulfite additioncompounds of glyoxal, glyoxylate and benzaldehyde were moreeffective in this respect than those of formaldehyde and acetaldehyde.
- The presence of -hydroxysulfonate causes an increase in ratiosof :14CO2 incorporated in glycolate and alanine, and a decreasein incorporation in serine, malate, isocitrate and citrate.It was inferred that these changes are caused by the blockingof the formation of glyoxylate through inhibition of glycolicacid oxidase by the poison.
- A reaction scheme was proposedto account for the above-statedresults, and the bearing ofthese findings on the possible roleof glycolic acid oxidasein the photosynthetic carbon dioxidefixation and in the formationof amino and organic acids wasdiscussed.
9.
- An enzyme possessing a capacity of catalyzing reduction of thecopper protein, plastocyanin, with reduced pyridine nucleotides(TPNH-plastocyanin reductase) was isolated from Chlorella ellipsoidea.The procedures of purification and the properties of the purifiedenzyme are described.
- From the results of chromatographicand enzymic tests, the prostheticgroup of the enzyme was identifiedas FAD. No evidence was obtainedto indicate the participationof metal ions in the reaction.
- The enzyme utilizes both TPNHand DPNH as electron donors, butthe reaction is about 12 timesfaster with TPNH than with DPNH.
- The enzyme, with TPNH aselectron donor, catalyzes the reductionof Chlorella plastocyanin,cytochrome c, 2,6-dichlorophenolindophenol and oxygen in adecreasing order of reaction rate.The reaction with oxygenas electron acceptor was found to bemuch more strongly acceleratedby the addition of higher concentrationsof flavins as comparedwith the reaction with other acceptors.FAD and FMN added tothe reaction mixture are not appreciablyreduced.
- The propertiesof the enzyme are compared with those of alliedchloroplastenzymes reported by various investigators and thepossible roleof the new enzyme in photosynthesis is discussed.
10.
- Using intact cells of Chlorella ellipsoidea, investigationswere made on the effects of some SH-reagents (IAA, CMB and arsenite)upon various reactions pertaining to the primary photogenicagent (designated by R) formed in the mechanism of photosynthesis.
- The pre-illumination experiments using 14CO2 as a tracer haveled us to the inference that (i) the process of photochemicalformation of R is inhibited by IAA, that (ii) the spontaneousdecay of R in the dark is markedly accelerated by CMB and arsenite,but not at all affected by IAA, and that (iii) the participationof R in the cyclic path of carbon leading to the fixation ofCO2 is not affected by IAA and CMB.
- Based on the assumptionthat R is a reducing agent, it was discussedthat the fact mentionedunder (iii) is incompatible with theidea that the reductionof PGA to triose phosphate be the soleor rate-determining reductivestep in the cyclic path of carbonin photosynthesis.
- The possibilitythat R may have a functional SH-group (s) wasinvoked to accountfor the observation that the decay of R inthe dark was markedlyaccelerated by CMB and arsenite.
11.
- The cells of Thiobacillus thiooxidans, which had been in contactwith sulfur or sulfide in air (or CO2-free air), could fix addedCOa very rapidly after replacing air with nitrogen. This fixationis designated as the postoxidative fixation.
- "Preoxidation"of the sulfur compounds is mandatory for theoccurrence of thepostoxidative fixation.
- The cells which had preliminarilyoxidized sulfide could notshow the CO2-fixation, when theywere placed under an anaerobiccondition in the absence of thesulfur compound.
- These results indicate that sulfur compoundsmay have an importantrole as the electron donor for the reductionof CO2, besidestheir role as the substrate of respiration tosecure energyfor the fixation of CO2
12.
Light-induced changes of b-type cytochromes in Euglena chloroplastswere studied spectrophotometrically.
- In the dark and at pH 6.5, most of the cytochrome 558 in chloroplastswas in the reduced state, and most of the cytochrome 563, inthe oxidized state. Illumination of chloroplasts at pH 6.5 induceda rapid, but slight oxidation of cytochrome 552 and cytochrome558. The magnitude of photooxidation of cytochrome 558 was greatlyenhanced by the addition of 3-(3',4'-dichlorophenyl)-1,1-dimethylurea(DCMU). The rate of photooxidation in the presence of DCMU wasstimulated by the addition of 0.15 µM Euglena cytochrome552, or 100 µM methyl viologen.
- Euglena chloroplasts,incubated at 55°C for 5 min showedno significant absorbancechanges for about 10 min after theonset of illumination. However,greater photooxidation of cytochrome558 was observed afterprolonged illumination, or in the presenceof DCMU or ethylenediaminetetraaceticacid (EDTA). Similar resultswere obtained with chloroplastspre-treated at pH 9.010.0for 5 min.
- At pH 9.5, andin the dark, both cytochrome 563 and cytochrome558 were inan almost reduced state. On illumination at thispH, both cytochromeswere photooxidized, with a complicatedkinetics, showing aninitial rapid and small absorbance decrease,followed by a stagnantphase of temporary retarded reaction.In the presence of DCMUor EDTA, photooxidation proceeded rapidlywithout a stagnantphase.
- At pH 6.5 cytochrome 558, on cessation of illumination,wasquickly reduced to the initial level. At pH 9.5, there wasalsoappreciable re-reduction of cytochrome 558 and 563 whenthelight was turned off at an early stage of illumination.Theamounts of re-reduction of the cytochromes in the subsequentdark period, however, decreased as photooxidation of cytochromesproceeded. This decrease was accelerated by the presence ofDCMU.
- At pH 9.5 ascorbate and manganese served as electrondonorsfor die DCMU-sensitive photooxidation of cytochromes558 and563.
- Experimental results are discussed with specialreference tothe occurrence of two pools of electron carriers,one at thereducing side and the other at the oxidizing sideof photosystem2. The role of manganese in the latter pool ofelectron carriersis also discussed.
13.
- 1. Analyses of cytochrome types in intact cells of aerobically-and anaerobically-grownPs. denitrificans indicated a higherratio of cytochrome c to cytochrome b in the former than inthe latter.
- 2. Anaerobically-grown cells contained about twotimes as muchcryptocytochrome c as did aerobically-grown cells.
- 3. Crystalline cryptocytochrome c obtained from the solublefraction of cell-free extracts of aerobically-grown cells manifestedthe same properties as cryptocytochrome c from anaerobically-growncells, i. e., absorption maxima, autooxidizability, redox potential,molecular weight, haem content, etc.
- 4. Cryptocytochrome cwas reversibly converted to a true haemochrometype spectrumby alcohols, detergents, carboxylic acid salts,guanidine saltor high pH values.
14.
- The photochemical conversion between the precursors of phycocyaninand phycoerythrin in Tolypothrix tenuis was investigated.
- Itwas found that the conversion of phycocyanin-precursor intophycoerythrin-precursor was induced by green light, and thereverse reaction by red light. These reactions proceeded exponentially, indicating that the photochemical process was acceleratedautocatalytically by the reaction-product.
- The rates of thesephotochemical reactions were found to beunaltered by varyingthe incubation temperature (0? to 35?)and the composition ofthe gas atmosphere (presence or absenceof CO2 and of O2 orby an inhibitor of photosynthesis, p-chlorophenyldimethylurea.
- The action spectra of the photochemical interconversions betweenprecursors of phycobilin chromoproteids were found to be distinctlydifferent from the absorption spectra of chlorophyll and carotenoids.The most effective wavelength for inducing the conversion ofphycocyanin- into phycoerythrin-precursor (541 mµ) isnear the absorption maximum of phycoerythrin (565 mµ),and that of the reverse reaction (641 mµ) is near theabsorption maximum of phycocyanin (620 mµ). Additionaldata, indicating that the phycobilin chromoproteids themselvesdo not participate in these processes as light absorber, werealso presented.
- On the basis of these results, a possiblemechanism of the photochemicalinterconversion between the precursorsof phycobilin chromoproteidsis proposed.
15.
- Lactate oxidation system was investigated in Acetobacter suboxydans,which was found to have cytochromes a and b, but no cytochromec. Haemoprotein 558 was also found to exist.
- Carbon monoxideinhibited the lactate oxidation in the darkbut not in the light.WARBURG'S partition constant was estimatedto be 7.
- Additionof haemoprotein 558 noticeably enhanced the oxygenuptake bythe LDH preparation, which was obtained from bacterialcellsand partially purified.
- Haemoprotein 558 has protohaem asits prosthetic group. Notonly its absorption spectrum is reminiscentof that of peroxidase,but it also shows peroxidase-like reactivitywith some ligandswith a few exceptions.
- Ferrohaemoprotein558 reacts with oxygen, forming, at first,a complex, whichhas its SORET absorption peak at 423 mµ.The absorptionmaximum then shifts to 417 mµ, indicatinga transformationto another compound. One of these two productsis likely tobe the oxygenated ferro-haemoprotein 558.
- The mutual transformationbetween cytochrome B and haemoprotein558 is discussed.
16.
CHIBA YASUTANE; AIGA ICHIRO; IDEMORI MASAHIRO; SATOH YOKO; MATSUSHITA KAMEHISA; SASA TSUTOMU 《Plant & cell physiology》1967,8(4):623-635
- The relation between chlorophyll content and the hydrolyticactivity of chlorophyllase in Chlorella protothecoides was examined.An increase in the activity was parallel to that in chlorophyllcontent during the development of green colouration, or greeningcourse, in the bleached cells. The activity sharply declinedand a parallel disappearance of chlorophyll was also found duringbleaching of the green cells.
- A partially purified water-solublepreparation of chlorophyllasewas obtained by n-butanol treatmentand fractionation with coldacetone. It showed high activityand hydrolyzed 2 mg chlorophylla per hr per mg protein.
- Forseparation and identification of the pigments concernedin thechlorophyllase reaction, a new solvent system of paperchromatographywas introduced.
- When methyl chlorophyllide a and phytol wereincubated withthe enzyme, two products were formed. By comparisonwith theRf values of isolated pure substances, one was identifiedaschorophyll a and the other as chlorophyllide a. This enzymedid not catalyze the phytylation of free chlorophyllide a, butit had the ability to attach phytol to methyl chlorophyllidea. The final step in the biosynthesis of chlorophyll a is brieflydiscussed.
17.
Carbon Monoxide Oxidation by Clostridium thermoaceticum and Clostridium formicoaceticum 总被引:30,自引:18,他引:12
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Cultures of Clostridium formicoaceticum and C. thermoaceticum growing on fructose and glucose, respectively, were shown to rapidly oxidize CO to CO2. Rates up to 0.4 μmol min−1 mg of wet cells−1 were observed. Carbon monoxide oxidation by cell suspensions was found (i) to be dependent on pyruvate, (ii) to be inhibited by alkyl halides and arsenate, and (iii) to stimulate CO2 reduction to acetate. Cell extracts catalyzed the oxidation of carbon monoxide with methyl viologen at specific rates up to 10 μmol min−1 mg of protein−1 (35°C, pH 7.2). Nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate and ferredoxin from C. pasteurianum were ineffective as electron acceptors. The catalytic mechanism of carbon monoxide oxidation was “ping-pong,” indicating that the enzyme catalyzing carbon monoxide oxidation can be present in an oxidized and a reduced form. The oxidized form was shown to react reversibly with cyanide, and the reduced form was shown to react reversibly with alkyl halides: cyanide inactivated the enzyme only in the absence of carbon monoxide, and alkyl halides inactivated it only in the presence of carbon monoxide. Extracts inactivated by alkyl halides were reactivated by photolysis. The findings are interpreted to indicate that carbon monoxide oxidation in the two bacteria is catalyzed by a corrinoid enzyme and that in vivo the reaction is coupled with the reduction of CO2 to acetate. Cultures of C. acidi-urici and C. cylindrosporum growing on hypoxanthine were found not to oxidize CO, indicating that clostridia mediating a corrinoid-independent total synthesis of acetate from CO2 do not possess a CO-oxidizing system. 相似文献
18.
- Several factors affecting sporulation of a wild yeast, Hansenulasaturnus, especially carbon sources and the carbon-nitrogenratio of sporulation medium were studied.
- The sporulationis stimulated at a certain definite C/N ratioof glucose medium.
- Several carbon sources such as ethanol, acetate, lactate,glycerol,succinate, glucose, gluconate and citrate are utilizedby theorganism both for growth and sporulation.
- The numberof spores in an ascus depends on the C/N ratio ofthe medium.An increase in the ratio stimulates the yield of2-and 3-sporedasci, especially of the former. One-spored ascibecome abundantas this ratio decreases.
- Lysine promotes sporulation in anacetate medium, and its presencein a large amount in glucosemedium also stimulates sporulation,while a small amount isinhibitory. When lysine was employedas the sole nitrogen source,most of the asci were 1-spored.
- It is discussed that sporulationof yeast is induced by a balanceof metabolism, rather thanby one definite "sporulation substrate".
19.
- A substance which inhibits indoleacetic acid (IAA)-and naphthaleneaceticacid (NAA)-induced elongation of Avena coleoptile section andIAA-induced Avena coleoptile curvature was found in an ethersoluble neutral fraction of water extract of sunflower leavesand in agar blocks containing the diffusate from young sunflowerleaves.
- This substance also inhibits the growth of isolatedsunflowerepicotyl.
- The Rf value (0.9) of the substance ona paper chromatogramdeveloped with ammoniacal iso-propanolindicates that it isidentical with the inhibitor reported byAUDUS et al. (1956),but not with inhibitor-ß.
- Theinhibitor can be transported from leaf to stem, and thetransportseems to be accelerated by illuminating the leaf.
- The auxindiffused from sunflower leaf into agar block may beidenticalwith IAA.
- A substance, which has the same properties as theinhibitorfrom sunflower leaf, was obtained in crystalline formfrom theleaf of Jerusalem artichoke.
- The mechanism of growthinhibition caused by this crystallinesubstance seems to involveinactivation of a sulfhydryl group.
- The reason why the stemgrowth of sunflower seedlings is reducedby strong light isdiscussed: the amount of the inhibitor transportedfrom leafto stem is increased under strong light, and in thestem, growthinhibition is caused by a direct effect of thisinhibitor ongrowth and by its inhibiting effect on the transportof IAAfrom leaf to stem.
20.
- Two neutral plant hormones, one isolated recently from plants(3-indolylacetonitrile) and the other (3-indolylacetaldehyde)reported to be present in plants, are avaible as pure syntheticcompounds for investigation of their biological activities.This paper is mainly concerned with their effects on cellelongationin the Avena coleoptile
- 3-Indolylacetaldehyde is considerablyless active than 3-indolylaceticacid in the Avena straight-growthtest; for example, a 1.0 mg./l.solution of the aldehyde showsan activity equivalent to thatof a 0.1 mg./l. solution of theacid
- An acidic substance is produced in solutions of the aldehydeduring the period of assay. In some experiments it accountsfor all of the activity shown by the aldehyde solutions, onthe assumption that it is 3-indoylacetic acid, and in otherexperiments it shows a greater activity than that of the aldehydesolutions from which it was obtained. Therefore, it is concludedthat 3-indolylacetaldehyde, itself is either inactive or inhibitory.Acid production in aldehyde solutions in vitro is much lower,a fact which suggests that there is enzymatic oxidation of aldehydeto acid in the presence of coleoptiles.
- The activities of3-indolylacetaldehyde in the pea test andin root-inhibitionand of 3-indolylacetone in the straight-growthtest are brieflyreported.
- 3-Indolylacetonitrile is considerably more activethan 3-indolylaceaticacid in the Avena straight-growth test;for erample, a 0.1 mg./l.solution of the nitrile shows an activityequivalent to a 1.0mg./l. solution of the acid. The inhibitoryeffect at concentrationsabove 1.010.0 mg./l. is lesswith the nitrile than withthe acid.
- There is negligible productionof acid in solutions of the nitrileboth in vitro and in thepresence of Avena coleoptiles at temperaturesranging from 18?to 25? C. for varying lengths of time.The possibility of enzymaticconvesion of nitrile to acid insidethe cells of the coleoptileis discussed
- The activities of 3-indolylacetamide and of 2:4-dichlorophenoxyaceticacid and the corresponding nitrile are considered in this connexion
- The nitrile is destroyed by treatment with alkali but notbyacid. In the light of these results, it is desirable to re-examineprevious work on identification of auxins in plants by theiracid and alkali sensitivity. Evidence for the existence of thenitrile in a number of other plants is presented.