The mechanism of indoleacetic acid oxidase reaction catalyzed by turnip peroxidase

Yamazaki, Isao; Souzu, Hiroshi

doi:10.1016/0003-9861(60)90421-5

Cited by 79 publications

(21 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This enzyme is more specific in its action and may represent a true IAA oxidase. The fact that a similar enzyme can be recovered from commercial, crystalline horseradish peroxidase suggests that IAA oxidase may be primarily responsible for oxidation of IAA in systems in which horseradish peroxidase has been used as the catalyst (3,6,7,23 (6) for horseradish peroxidase and by Ray (14) for the Omphali(a enzvme. W;ith all these enzymes, increases in absorption at approximately 254 and 247 m, concurrent with IAA oxidation have been reported.…”

Section: Discussionmentioning

confidence: 99%

“…2 Published witlh the approval of the Director, Wiscou0s1in Agrictultural Experimenit StatioII. Project 1209. dase therefore behaves as a typical peroxidase, btit apparently is liniked to an aerobic system which produces H202 as a resuilt of the reactioni of free radical intermediates with 02 (23). Fuirther evideence for the peroxidase natuire of the enzyme was obtainied by Sttutz (21), who failed to separate IAA oxi(dase from peroxidase in preparationis from L'ptri1s by means of starch block electrophoresis.…”

mentioning

confidence: 98%

“…Some workers (23) consi(ler that the initiation of the reaction, dturing the induiction phase, depends tipon traces of H.,O, in the system. Since H,O , when added to the sy-stem, will remove the lag period, it would appear that TIMO.2 either is or is converted into a reaction interme(liate essential in an autocatalytic cyclical reactiotn (15).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Partial Purification and Kinetics of Indoleacetic Acid Oxidase from Tobacco Roots

1966

View full text Add to dashboard Cite

dase therefore behaves as a typical peroxidase, btit apparently is liniked to an aerobic system which produces H202 as a resuilt of the reactioni of free radical intermediates with 02 (23). Fuirther evideence for the peroxidase natuire of the enzyme was obtainied by Sttutz (21), who failed to separate IAA oxi(dase from peroxidase in preparationis from L'ptri1s by means of starch block electrophoresis.In attempts to correlate changes in IAA oxidlase activity in diseased tobacco tissuies (19) with the acctumtllation of phenolic inhibitors, it was nloted that the enzyme system from tobacco roots followved tuntustual kinetics. Highly active preparations did not exhibit the indtuction period typical of IAA oxidase from other souirces (17). It was felt that these resuilts couild be due to the simuiltanieouis action of IAA oxidase and a separate peroxi(lase in the system. It was also noted that fresh extracts from tobacco roots contained both IAA oxidase and peroxidase activities, but the ability to oxidize IAA disappearedl after the preparations were lyophilized or stored at -100 for several weeks, whereas the activity on polyphenols remained unaffected. The thermal inactivation points and the pH optima for both oxidations were different. \Vhereas these observations were not inconsistent with the view that a single enzyme with 2 separate centers for suibstrate attachment was involved, it seemed more 1200 www.plantphysiol.org on May 9, 2018 -Published by Downloaded from

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 98%

See 1 more Smart Citation

Partial Purification and Kinetics of Indoleacetic Acid Oxidase from Tobacco Roots

1966

View full text Add to dashboard Cite

show abstract

“…Complications due to enzyme inactivation were avoided in the present study by using ratios of peroxidase to H202 of I x 10-6 or greater. Although the complete mechanism of IAA oxidation by peroxidases is still unknown, the involvement of endogenous H202 in the initiation and propagation of the reaction has been proposed by several investigators (3,22,23 (8,13,17) is responsible for the observed 02 uptake. The sequence of these events is depicted in the following set of reactions:…”

Section: Methodsmentioning

confidence: 99%

Hydrogen Peroxide-mediated Oxidation of Indole-3-acetic Acid by Tomato Peroxidase and Molecular Oxygen

Kokkinakis

Brooks²

1979

Plant Physiol.

View full text Add to dashboard Cite

The oxidation of indoe-3-acetic acid by anionic tomato peroxidase was found to be neglUige unless reaction mixtures were supplemented with H202. The addition of H202 to reaction mixtures initiated a period of rapid indole-3-acetic acid oxidation and 02 uptake; this phase ended and 02 uptake fell to a low level when the H202 was exhausted. The stoichiometry of the reaction, which is highly dependent on enzyme concentration and pH, suggests that H202 initiates a sequence of reactions in which indole-3-acetic acid is oxidized.Many plant peroxidases catalyze the oxidation of IAA by molecular 02 in the presence of a phenol and manganous ion (2,6,10,14,16 MATERIALS AND METHODSEnzyme Source and Estimation. Tomato anionic peroxidase was extracted from tomato (Lycopersicon esculentum var. tropic) pericarp tissue and purified to about 85% homogeneity as previously described (11). Enzyme concentrations were estimated from the 403 nm A of solutions, using a millimolar extinction coefficient of 107 for the enzyme (11). A spectra from 400 nm to 600 nm wavelength were run on a Perkin-Elmer 124 spectrophotometer and associated chart recorder and used to determine if the enzyme was present as ferric enzyme, ferrous enzyme, compound I, compound II, or compound III (11

show abstract

“…This interference appears to be specific for IAA, since the substitution of NAA, which is not a substrate of IAA oxidase (13) 3. In the presence of an excess of H202 and a fixed concentration of Fo, the voltage (Eo.,) was observed to vary as a linear function of added (IAA) (Fig. 4) (2,8,16). Experiments are planned to clarify the basis for these differences in peroxidative characteristics.…”

Section: Discussionmentioning

confidence: 96%

The Use of an Enzyme Electrode in the Analysis of Indole-3-acetic Acid Oxidase Activity in Avena

McCreight

Perley²

1974

Plant Physiol.

View full text Add to dashboard Cite

A flexible analytical system which allows for the continuous potentiometric monitoring of the disappearance of an electrochemical species, ferrocyanide, by the peroxidase enzyme is described. The ability of peroxidase to mediate the oxidation of indole-3-acetic acid is followed by observing the competition of indole-3-acetic acid with ferrocyanide for the peroxidase enzyme. This is accomplished by examining potentiometrically the decrease in the rate of ferrocyanide oxidation with increasing indole-3-acetic acid concentration. Homogenates of Avena sativa coleoptiles are investigates for both peroxidase and indole-3-acetic acid oxidase activity. (2,4,5,7,9,13). It has been suggested that the IAA-oxidase system may function as a plant growth regulating mechanism because of its role in limiting the supply of IAA within the plant.Quantitative determinations of IAA oxidase activity have generally been limited to three basic assay approaches for IAA: (a) physiological response to IAA in decapitated Avena coleoptiles (13), (b) absorbance changes at 261 nm (11), and (c) colorimetric determination of indoles with Salkowski reagent (6,14). The latter technique depends on the development of a pink colored complex with Fe3`in the presence of a concentrated mineral acid. However, Perley and Stowe (10) ( 1) where: AH = donor in reduced form, A = donor in oxidized form to the oxidation of IAA by the reaction peroxidase IAA + H202 -* IAAoxidized + H20(2) or attributed to a competition between IAA and the electron donor species (AH) for H202. According to Ray, the results suggested that in the presence of both substrates, an inactive form of the enzyme, incapable of oxidizing either of them, accumulates.We report here a slightly different interpretation of the interactions of the peroxidase and IAA oxidase systems, based on observations made by means of a new continuous flow, potentiometric technique developed first by R. I. Porterfield and C. L. Olson of the Ohio State University (personal communication) employed in this laboratory to study the peroxidase-IAA oxidase systems. The advantages and problems posed by this new analytical system, as well as several further applications, are discussed. MATERIALS AND METHODSPlant Culture and Homogenate Preparation. Oats (Avena sativa cv. Victory) were grown on water-saturated cotton in complete darkness at 23 C. At from 8 to 18 days, the etiolated coleoptiles and primary leaves were cut off in the light at 5 C, weighed, placed in 0.15 M potassium phosphate buffer (pH 6.20), and homogenized for 3 min in a Waring Blendor. The brei was then pressed through four layers of cheesecloth, centrifuged at 25,000g for 15 min at 5 C, and the supernatant decanted. This supernatant, which contained the plant enzyme studied, was used immediately without further purification or separation.Analytical System. The experimental apparatus consisted of four components and plastic tubing (Tygon through the pump,

show abstract

The mechanism of indoleacetic acid oxidase reaction catalyzed by turnip peroxidase

Cited by 79 publications

References 17 publications

Partial Purification and Kinetics of Indoleacetic Acid Oxidase from Tobacco Roots

Partial Purification and Kinetics of Indoleacetic Acid Oxidase from Tobacco Roots

Hydrogen Peroxide-mediated Oxidation of Indole-3-acetic Acid by Tomato Peroxidase and Molecular Oxygen

The Use of an Enzyme Electrode in the Analysis of Indole-3-acetic Acid Oxidase Activity in Avena

Contact Info

Product

Resources

About