Isolation from Peas of Co-Factors and Inhibitors of Indolyl-3-Acetic Acid Oxidase

Furuya, Masaki; Galston, Arthur W.; Stowe, Bruce B.

doi:10.1038/193456a0

Cited by 121 publications

(39 citation statements)

References 9 publications

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“…It is seen that the growth repression of wheat coleoptiles when incubated with HRP and IAA is s-ignificantly reversed by HCG. The action of the gonadotropin in this respect resembles the effect of diphenols on the above IAA-enzyme interaction (4).…”

Section: Discussionmentioning

confidence: 85%

Presence and Possible Mode of Action of a Proteinaceous Gonadotropin-like Growth Regulating Factor in Plant Systems

et al. 1969

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Abstract. Antiserum to human chorionic gonadotropin (HCG) caused marked inhibition of adventitious rooting of Begonia semperflorens and Chrysanthemum morifolium stem cuttings. Immuno-absorption of crude protein extract from chrvsanthemum foliage through a column of polymerized and unsolubilized HCG antibodies resulted in a significant reduction in adventitious root promoting activity of the extract. These results are discussed in the light of a hypothesis that an endogenous protein growth regulating substance which immunologically resembles HCG exists in plant systems. Further experimentation with HCG suggests that its mode of action is possibly via the regulation of peroxidase enzymatic control of auxin levels.In previous studies Leshem (10) and Leshem and Lunenfeld (11) have shown that HCG, a proteinaceous human sex hormone, has growth stimulating effects on certain morphogenetic processes in plants, especially upon adventitious rooting of Vitis vinifera, Begonia semperflorens and Brassica oleracea. It was shown that HCG possibly acts via regulation of endogenous gibberellin levels, the latter being markedly repressed by the gonadotropin, and a hypothesis was suggested that HCG triggers mevalonic acid conversion to steroids thereby diminishing precursor for gibberellins.In the present study bv use of immunological techniques an attempt has been made to indicate the existence of an endogenous gonadotropin-like proteinaceous growth regulating factor in plants. Fur-ther experimentation was carried out in order to elucidate the mode of HCG action in plant systems, especially in the light of hormone-enzyme interactions which are prevalent both in plant (3,7,13,14,15,21) One ml of the antiserum neutralized 600 International Units (IU) of HCG as determined by the procedure of Loraine and Brown (12). As control active rabbit serum lacking HCG antibodies was tised.The approach used in the immuno-absorption trials was as follows: If a protein extract of plant material were to be passed through a medium conitaining HCG antibodies, the effluent would be depleted of any existent endogenous HCG or any immunologically similar antigenic substances which could "cross react" with the antibodies (1) and resultinglv evoke a weaker growth stimulating response. This system was obtained by insolubilizing HCG antibodies by covalent binding of the molecules to one another with ethyl-chloroformate using the technique described by Avramaes and Ternynck (2).The immunoabsorbent properties of such insolubilized proteins were found by these workers to be specific, stable and effective to isolate specific antigens from mixtures and to remove contaminating antigen proteins from solutions. The protein obtained in this manner was packed in a 50 cm X 3 cm 4 glass column through which protein extract was subsequently passed. In order to determine whether this procedure does actually work in the present trials, various concentrations of HCG solutions were run through test columns and resulting effluents were assayed for presence of HCG by immuno-...

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Section: Discussionmentioning

confidence: 85%

Presence and Possible Mode of Action of a Proteinaceous Gonadotropin-like Growth Regulating Factor in Plant Systems

et al. 1969

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“…Initial rates of reaction were plotted froml optical density readings taken at 10 sec intervals for 2 mimi. For studies on the inhibition of peroxidase activity by organic acids and 2,4-dichlorophenol, 3 umoles of these compouinds were added to the above in 0.1 ml. Controls contained 0.1 ml water.…”

Section: Resultsmentioning

confidence: 99%

“…This was accomplished either by prolonged washing in the ultrafilter, or by evaporation of extract to a paste and dissolving in water. The crude enzyme used to obtain the data recorded in figure 2 IAA-oxidase activity was restored upon addition of 3 Mtmoles of malic acid to the reaction mixture (fig 2).…”

Section: Resultsmentioning

confidence: 99%

“…IAA-oxidase is inhibited int vitro by catalase (4,5,11), polyphenols (1,3,7,14), various inhibitors and substrates of peroxidase (6,20), and by unidentified constituents of plant extracts (13,19). A number of phenols act in vitro either as inhibitors or co-factors, and a rather extensive literature provides a tacit support for the function of phenols in these roles in the plant.…”

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Stimulation of Indoleacetic Acid Oxidase and Inhibition of Catalase in Cotton Extracts by Plant Acids

Lane

King

1968

Plant Physiol.

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Abstract. Aotivity of indoleacetic acid oxidase in partially purified extracts from cotton is stimtulated by small amounts of malate, suocinate, fumarate, and other plant acids. The stimulation is apparently due to inhibition of catalase, which is detectable in certain preparations. The 4ag phase of indeleacetic acid oxidation by crude preparations is eliminated by steps in processing which oonceivably either denatures or dilutes catalse, or concentrates inhibitors to catalase.IAA-oxidase is inhibited int vitro by catalase (4, 5, 11), polyphenols (1, 3, 7, 14), various inhibitors and substrates of peroxidase (6,20), and by unidentified constituents of plant extracts (13,19). A number of phenols act in vitro either as inhibitors or co-factors, and a rather extensive literature provides a tacit support for the function of phenols in these roles in the plant.The possibility of regulation of IAA-oxidase by catalase in vivo has received surprisingly little emphasis. This has probably followed the observation of Goldacre et al. l(6) that phenols stimulate IAA-oxidase of peas in the absence of catalase. In efforts to partially purify IAA-oxidase from cotton roots, Lane (12) found that the protein (enzyme) fraction was separated from certain plant acids with a complete loss of IAA-oxidase activity. Addition of a small amount of any one of several organic acids restored activity completely.Noting that these same acids are inhibitors of catalase, we determined the effect of several acids on activities of catalase, peroxidase and IAA-oxidase in extracts of cotton. Results and DiscussionPlant Ciiltu(re. ,tmoles in 0.1 ml of water. Except whein noted, 2,4-dichlorophenol was not lused. All assays were conducted using 1 ml of enzyme soluttion, regardless of extent of concentration.Catalase. Decomposition of 110., was monlitored spectrophotometrically at 240 nm at 250, The reaction mixture contained 2 ml plant extract at appropriate dilution and 1 ml 0.059 M H.202 in 0,05 M phos,phate buffer, pH 7.0.For studies on the inhibition of catalase activitv by organic acids and 2,4-dichlorophenol, 3 tumoles of these compounds were added to the above in 0.1 ml. Controls contained 0.1 ml water. Initial rates of reaction were plotted froml optical density readings taken at 10 sec intervals for 2 mimi.Peroxidase. Appearanice of 8-aminoqu-i,noline oxidation prodtuct was monitored spectrophotometri-1699 www.plantphysiol.org on May 10, 2018 -Published by Downloaded from

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“…Indirect evidence suggesting a role in dormancy and in root and shoot growth has been presented by Harborne (11). It was determined that kaempferol (3,5,7,4'-tetrahydroxyflavone) was a cofactor for in vitro IAA oxidase while quercetin (3,5,7,3',4'-pentahydroxyflavone) inhibited the activity of the enzyme (6). Stenlid (16) conducted an extensive survey of the effects of many flavonoids on ATP production by mitochondria isolated from several plant species.…”

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Kaempferol Inhibitions of Corn Mitochondrial Phosphorylation

Koeppe

Miller²

1974

Plant Physiol.

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Kaempferol (3,5,7,4'tetrahvdroxyflavone) inhibited the rate of state 3 substrate oxidation, but not the state 4 rate. This, along with the kaempferol inhibition of substrate-driven calcium-phosphate deposition, provided evidence that kaempferol was acting specifically on the phosphorylation mechanism and not on electron transfer. Kaempferol, however, did not inhibit ATP-driven contraction while oligomycin did. Comparisons of kaempferol with mersalyl indicated that kaempferol did not inhibit phosphorylation by blocking phosphate transport. Both kaempferol and 2, 4-dinitrophenol inhibited calcium-phosphate transport, but kaempferol did not stimulate respiration to the extent that 2, 4-dinitrophenol did under acceptorless conditions. Kaempferol had no effect on NADHdriven contraction in a potassium chloride reaction medium. The site of kaempferol effect is thus seen to be unique from oligomycin and more like aurovertin, likely acting before the formation of the phosphorylated high energy intermediate, but not as an uncoupler in the traditional 2,4-dinitrophenol mode.Flavonoid compounds have been reported to be distributed widely throughout the plant kingdom (11). Despite this wide distribution, little evidence has been presented linking their occurrence with a role in growth or metabolism. Indirect evidence suggesting a role in dormancy and in root and shoot growth has been presented by Harborne (11). It was determined that kaempferol (3,5,7,4'-tetrahydroxyflavone) was a cofactor for in vitro IAA oxidase while quercetin (3,5,7,3',4'-pentahydroxyflavone) inhibited the activity of the enzyme (6). Stenlid (16) conducted an extensive survey of the effects of many flavonoids on ATP production by mitochondria isolated from several plant species. From this work it is evident that minor changes in the hydroxyl pattern affect the degree of inhibition of ATP formation. The work of Stenlid (16) chloroplasts (20). Kaempferol glucosides were a major component of the flavonoids quantitated.Galston (7) has hypothesized from data with quercetin and kaempferol glucosides that flavonoids could play a broadly significant role in contractile and membranous phenomena in plants. Such possibilities would involve transport mechanisms associated with the production and utilization of high energy bonds, most probably as ATP and would thus suggest a possible interaction of mitochondria and flavonoids under certain conditions in vivo. In vitro mitochondrial experiments in which these interactions are studied should be useful in the furtherance of hypotheses such as Galston's (7).When the specific effects of kaempferol on mitochondrial mechanisms for oxidative phosphorylation are being considered, several sites of action are possible as evidenced in studies with other inhibitors. These include the oligomycinsensitive site in some way associated with X P (3), the DNPtsensitive site most likely associated with a proton-motive force or the nonphosphorylated intermediate (2,8,15), or the mersalyl-sensitive site associated with phosphat...

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Isolation from Peas of Co-Factors and Inhibitors of Indolyl-3-Acetic Acid Oxidase

Cited by 121 publications

References 9 publications

Presence and Possible Mode of Action of a Proteinaceous Gonadotropin-like Growth Regulating Factor in Plant Systems

Presence and Possible Mode of Action of a Proteinaceous Gonadotropin-like Growth Regulating Factor in Plant Systems

Stimulation of Indoleacetic Acid Oxidase and Inhibition of Catalase in Cotton Extracts by Plant Acids

Kaempferol Inhibitions of Corn Mitochondrial Phosphorylation

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