A Role for Peroxidase in Biosynthesis of Auxin

Riddle, V. M.; Mazelis, Mendel

doi:10.1038/202391a0

Cited by 39 publications

(5 citation statements)

References 3 publications

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“…Its occurrence has been challenged [23] because of isolation artifacts, although a later report avoided these problems [24]. Tryptophan can be converted into indole-3-acetamide by a peroxidase-catalyzed reaction, and therefore it has been implicated as natural intermediate in auxin biosynthesis [25,261. This was later considered to be an unspecific reaction not occurring in vivo, and thus recent reviews (e.g.…”

Section: Discussionmentioning

confidence: 99%

The T‐region of Ti plasmids codes for an enzyme synthesizing indole‐3‐acetic acid

Schröder¹,

Waffenschmidt²,

Weiler³

et al. 1984

European Journal of Biochemistry

346

129

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Gene 2 from the T region of Ti plasmids appears to be expressed both in eucaryotic and in procaryotic systems. In transformed plant cells it participates in auxin-controlled growth and differentiation, and in bacteria it is expressed into a defined protein of M, 49000. We investigated the possibility that it codes for an enzyme involved in auxin bi osynt hesis .Only extracts from Escherichia coli cells expressing gene 2 hydrolyzed indole-3-acetamide into a substance which was unambiguously identified as indole-3-acetic acid. The same reaction was found in Agrobacteria containing gene 2, but not in strains lacking the gene. Extracts from tobacco crown gall cells, but not from non-transformed cells, showed the same enzyme activity, and the reaction product was also identified as indole-3-acetic acid. The results indicate that gene 2 of the T region, which participates in tumorous growth of plant cells, codes both in bacteria and in plants for an amidohydrolase involved in the biosynthesis of the plant hormone indole-3-acetic acid.

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Section: Discussionmentioning

confidence: 99%

The T‐region of Ti plasmids codes for an enzyme synthesizing indole‐3‐acetic acid

Schröder¹,

Waffenschmidt²,

Weiler³

et al. 1984

European Journal of Biochemistry

346

129

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“…coli, A . Moreover, IAM may originate from Trp in vitro by the enzymatic activity of horseradish peroxidase [35,36] . Neither normal nor habituated tissue show this enzymatic activity.…”

Section: Iaa Level In a Tumefaciens-transformed Tissue Culturesmentioning

confidence: 99%

Auxin synthesis in Agrobacterium tumefaciens and A. tumefaciens-transformed plant tissue

Kutáček

Rovenská

1991

Plant Growth Regul

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“…The results with 2,6-dichloro-p-benzoquinone-4-chloroimine suggest that, unlike in the oxidation of pyridoxamine by peroxidase (Hill, 1970), the 3-hydroxypyridine structure was not changed. Amides have been identified as oxidation products in the oxidative deamination of methionine and tryptophan by pyridoxal phosphate and Mn2+ ions (Mazelis & Ingraham, 1962;Riddle & Mazelis, 1964) and amides are readily hydrolysed by NaOH; pyridoxal may also be oxidized to 4pyridoxic acid by this system (Hill & Mann, 1966). Therefore, as pyridoxal catalyses the oxidative deamination of pyridoxamine and is itself changed in the reaction, it is possible that in the oxidative deamination of pyridoxamine by oc-oxo acids and Mn2+ ions an amide, possibly that of pyridoxic acid or a related compound, is produced by a secondary reaction and that this would account for the low yields of pyridoxal and ammonia found, and for the increase in oxygen uptake.…”

Section: Discussionmentioning

confidence: 99%

The oxidation of Schiff bases of pyridoxamine with α-oxo acids by manganous ions and peroxidase

Hill

1972

Biochemical Journal

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1. Oxygen was taken up rapidly when pyruvate was added to mixtures of pyridoxamine and Mn(2+) ions after lag periods that were shortened by peroxidase (donor-hydrogen peroxide oxidoreductase, EC 1.11.1.7). 2. The total oxygen uptake was proportional to the pyridoxamine added and was accompanied by the disappearance of pyridoxamine; the pyruvate acted catalytically and hydrogen peroxide was not formed. 3. At pH6 more than half the pyridoxamine that disappeared was accounted for as pyridoxal and ammonia; it is suggested that the primary reaction is the oxidative deamination of the pyridoxamine. 4. Results were similar when alpha-oxobutyrate or glyoxylate were substituted for pyruvate, except that the reactions were slower and the yield of pyridoxal less. 5. The oxidative decarboxylations of alpha-oxoglutarate and phenylpyruvate are catalysed by Mn(2+) ions and these reactions are activated by peroxidase; pyridoxamine increased both the rates and total oxygen uptakes in these reactions, and ammonia was produced. 6. The lag periods in the oxidation of mixtures of pyridoxamine and alpha-oxo acids, catalysed by Mn(2+) ions, were also shortened by traces of colloidal manganese dioxide. 7. It is suggested that the activating effect of peroxidase depends on its catalysis of manganese oxidation.

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A Role for Peroxidase in Biosynthesis of Auxin

Cited by 39 publications

References 3 publications

The T‐region of Ti plasmids codes for an enzyme synthesizing indole‐3‐acetic acid

The T‐region of Ti plasmids codes for an enzyme synthesizing indole‐3‐acetic acid

Auxin synthesis in Agrobacterium tumefaciens and A. tumefaciens-transformed plant tissue

The oxidation of Schiff bases of pyridoxamine with α-oxo acids by manganous ions and peroxidase

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