scholarly journals Identification ofEscherichia coliHemG as a Novel, Menadione-Dependent Flavodoxin with Protoporphyrinogen Oxidase Activity

Biochemistry ◽  
2009 ◽  
Vol 48 (29) ◽  
pp. 6705-6711 ◽  
Author(s):  
Tye O. Boynton ◽  
Lauren E. Daugherty ◽  
Tamara A. Dailey ◽  
Harry A. Dailey
Keyword(s):  
Oxidase Activity ◽  
Protoporphyrinogen Oxidase

The use of leucocyte protoporphyrinogen oxidase activity in screening a family with variegate porphyria

1986 ◽  
Vol 14 (1) ◽  
pp. 153-154 ◽  
Author(s):  
JOSEPH BOYLE ◽  
XENIA HORDOVATZI ◽  
GEORGE G. THOMPSON ◽  
MICHAEL R. MOORE
Keyword(s):  
Oxidase Activity ◽  
Protoporphyrinogen Oxidase ◽  
Variegate Porphyria

scholarly journals An h.p.l.c. assay for protoporphyrinogen oxidase activity in rat liver

1987 ◽  
Vol 243 (3) ◽  
pp. 863-866 ◽  
Author(s):  
F Li ◽  
C K Lim ◽  
T J Peters
Keyword(s):  
Rat Liver ◽  
Oxidase Activity ◽  
Mitochondrial Protein ◽  
Protoporphyrin Ix ◽  
Internal Standard ◽  
Reversed Phase ◽  
Tissue Homogenate ◽  
Protoporphyrinogen Oxidase ◽  
Liver Tissue Homogenate

An h.p.l.c. method is described for the assay of protoporphyrinogen oxidase activity in rat liver. A relatively pure protoporphyrinogen IX substrate was obtained by selectively removing any protoporphyrin IX unreduced by sodium amalgam on a small disposable cartridge packed with a strong anion-exchanger. The protoporphyrin IX formed was extracted with dimethyl sulphoxide/methanol (3:7, v/v) containing mesoporphyrin as the internal standard for separation and quantification by reversed-phase chromatography. The Km for protoporphyrinogen was 9.5 +/- 1.6 microM, and the enzyme activities were 0.59 +/- 0.11 nmol of protoporphyrin IX produced/min per mg of mitochondrial protein and 33.5 +/- 2.7 nmol protoporphyrin IX produced/min per g of liver tissue homogenate. The method is applicable to the determination of enzyme activity in small amounts of human liver biopsy.

Isolation and Characterization of a Chlamydomonas reinhardtii Mutant Resistant to Photobleaching Herbicides

1993 ◽  
Vol 48 (3-4) ◽  
pp. 339-344 ◽  
Author(s):  
Hiromichi Oshio ◽  
Hideyuki Shibata ◽  
Nobuaki Mito ◽  
Masako Yamamoto ◽  
Elizabeth H. Harris ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Oxidase Activity ◽  
Higher Plants ◽  
Diphenyl Ether ◽  
Protoporphyrin Ix ◽  
Nuclear Genome ◽  
Photosynthetic Electron Transport ◽  
Wild Type ◽  
Protoporphyrinogen Oxidase ◽  
Isolation And Characterization

A group of highly active N -phenylimide photobleaching herbicides have been synthesized. These N -phenylimide herbicides as well as diphenyl ether herbicides induce protoporphyrin IX accumulation and inhibit protoporphyrinogen oxidase activity at extremely low concentrations in higher plants. The binding of a 14C -labeled N -phenylimide herbicide S-23121 [N-[4-chloro- 2-fluoro-5-[(1-m ethyl-2-propynyl)oxy]phenyl]-3,4,5,6-tetrahydrophthalimide] to the solubilized plastid fractions of greening corn seedlings is competed by the diphenyl ether herbicide acifluorfen-ethyl, but not by diuron, an inhibitor of photosynthetic electron transport. These results indicate a similar mode of action for both N -phenylimide and diphenyl ether herbicides.In order to investigate the mechanism of photobleaching herbicides at the molecular level, a strain of Chlamydomonas reinhardtii RS-3 resistant to N -phenylimide S-23142 [N -(4-chloro- 2-fluoro-5-propargyloxyphenyl)-3,4,5,6-tetrahydrophthalimide] was isolated by mutagenesis with N -m ethyl-N′-nitro-N -nitrosoguanidine. The 90% inhibition concentration of N -phenylimide S-23142 for growth of RS-3 was 100 times higher than that for wild type. Maximum accumulation of protoporphyrin IX was reached at 0.03 μᴍ of S-23142 for the wild type and 3 μᴍ for RS-3. RS-3 was resistant to oxadiazon, oxyfluorfen and acifluorfen-ethyl which had been shown to have the same mechanism of action as N -phenylimide herbicides, but not to paraquat, diuron or fluridone. Genetic analysis of RS-3 strain showed that the resistance results from a dominant mutation ( rs-3) in the nuclear genome. The magnesium protoporphyrin IX synthesizing activity from 5-am inolevulinic acid in chloroplast fragments isolated from RS-3 was less sensitive to S-23142 than that from wild type (CC-407). Protoporphyrinogen oxidase activity in Percoll™ -purified chloroplasts from RS-3 was also less sensitive to S-23142 than that from wild type. These results indicate that the resistance of RS-3 is specific for photobleaching herbicides, and that the mutation is related to protoporphyrinogen oxidase, the primary site of the photobleaching herbicide action.

Nucleotide sequence of the hemG gene involved in the protoporphyrinogen oxidase activity of Escherichia coli K12

1993 ◽  
Vol 39 (12) ◽  
pp. 1155-1161 ◽  
Author(s):  
Alexandre Sasarman ◽  
Jaroslav Letowski ◽  
Guy Czaika ◽  
Volta Ramirez ◽  
Michael A. Nead ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Oxidase Activity ◽  
Chlorophyll Biosynthesis ◽  
Protoporphyrin Ix ◽  
Translation System ◽  
Protoporphyrinogen Oxidase ◽  
Escherichia Coli K12 ◽  
Amino Terminal

The hemG gene of Escherichia coli K12 is involved in the activity of protoporphyrinogen oxidase, the enzyme responsible for the conversion of protoporphyrinogen IX into protoporphyrin IX during heme and chlorophyll biosynthesis. The gene is located at min 87 on the genetic map of E. coli K12. The hemG gene was isolated by a mini-Mu in vivo cloning procedure. As expected, the hemG gene is able to restore normal growth to the hemG mutant, and the transformed cells display strong protoporphyrinogen oxidase activity. Sequencing of the hemG gene allowed us to identify an open reading frame of 546 nucleotides (181 amino acids), within the minimal fragment able to complement the mutant. The presumed molecular mass of the HemG protein is 21 202 Da, in agreement with values found by SDS-PAGE, in a DNA-directed coupled transcription–translation system. The identity of the first 18 amino acids at the amino-terminal end of the protein was confirmed by microsequencing. To our knowledge, this is the first cloning of a gene involved in the protoporphyrinogen oxidase activity of E. coli.Key words: protoporphyrinogen oxidase (PROTOX), hemG gene, Escherichia coli, DPE herbicides, heme.

Measurement of Protoporphyrinogen Oxidase Activity

1999 ◽  
Vol 00 (1) ◽  
pp. 8.5.1-8.5.13 ◽  
Author(s):  
Judith M. Jacobs ◽  
Nicholas J. Jacobs
Keyword(s):  
Oxidase Activity ◽  
Protoporphyrinogen Oxidase
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