On the mechanism of citrate inhibition of ceruloplasmin ferroxidase activity

BioMetals ◽  
1996 ◽  
Vol 9 (3) ◽  
pp. 273-275 ◽  
Author(s):  
Rolf Arthur L�vstad
1999 ◽  
Vol 338 (3) ◽  
pp. 615-618 ◽  
Author(s):  
Xiaoke YANG ◽  
N. Dennis CHASTEEN

It is widely accepted that iron deposition in the iron storage protein ferritin in vitro involves Fe(II) oxidation, and that ferritin facilitates this oxidation at a ferroxidase site on the protein. However, these views have recently been questioned, with the protein ferroxidase activity instead being attributed to autoxidation from the buffer alone. Ligand exchange between another protein with ferroxidase activity and ferritin has been proposed as an alternative mechanism for iron incorporation into ferritin. In the present work, a pH stat apparatus is used to eliminate the influence of buffers on iron(II) oxidation. Here we show that the recent experiments questioning the ferroxidase activity of ferritin were flawed by inadequate pH control, that buffers actually retard rather than facilitate iron(II) oxidation, and that horse spleen ferritin has ferroxidase activity when measured under proper experimental conditions. Furthermore, high pH (7.0), a high Fe(II) concentration and the presence of Fe(III) all favour Fe(II) autoxidation in the presence or absence of ferritin.


BioMetals ◽  
2016 ◽  
Vol 29 (4) ◽  
pp. 691-704 ◽  
Author(s):  
Valeria A. Kostevich ◽  
Alexey V. Sokolov ◽  
Stanislav O. Kozlov ◽  
Anna Yu. Vlasenko ◽  
Nikolay N. Kolmakov ◽  
...  

2020 ◽  
Vol 71 (16) ◽  
pp. 4828-4842
Author(s):  
Hao Ai ◽  
Yue Cao ◽  
Ajay Jain ◽  
Xiaowen Wang ◽  
Zhi Hu ◽  
...  

Abstract Members of the Low Phosphate Root (LPR) family have been identified in rice (Oryza sativa) and expression analyses have been conducted. Here, we investigated the functions of one of the five members in rice, LPR5. qRT-PCR and promoter–GUS reporter analyses indicated that under Pi-sufficient conditions OsLPR5 was highly expressed in the roots, and specific expression occurred in the leaf collars and nodes, and its expression was increased under Pi-deficient conditions. In vitro analysis of the purified OsLPR5 protein showed that it exhibited ferroxidase activity. Overexpression of OsLPR5 triggered higher ferroxidase activity, and elevated concentrations of Fe(III) in the xylem sap and of total Fe in the roots and shoots. Transient expression of OsLPR5 in Nicotiana benthamiana provided evidence of its subcellular localization to the cell wall and endoplasmic reticulum. Knockout mutation in OsLPR5 by means of CRISPR-Cas9 resulted in adverse effects on Pi translocation, on the relative expression of Cis-NATOsPHO1;2, and on several morphological traits, including root development and yield potential. Our results indicate that ferroxidase-dependent OsLPR5 has both a broad-spectrum influence on growth and development in rice as well as affecting a subset of physiological and molecular traits that govern Pi homeostasis.


2015 ◽  
Vol 1850 (6) ◽  
pp. 1267-1273 ◽  
Author(s):  
Paola Ruzzenenti ◽  
Michela Asperti ◽  
Stefania Mitola ◽  
Elisabetta Crescini ◽  
Federica Maccarinelli ◽  
...  

1984 ◽  
Vol 32 (10) ◽  
pp. 4029-4035 ◽  
Author(s):  
SHINZO TANABE ◽  
TOSHIKO SHIOIRI ◽  
KYOKO MURAKAMI ◽  
TOSHIO IMANARI

BioMetals ◽  
2012 ◽  
Vol 25 (4) ◽  
pp. 687-695 ◽  
Author(s):  
Perungavur N. Ranganathan ◽  
Yan Lu ◽  
Brie K. Fuqua ◽  
James F. Collins

2002 ◽  
Vol 277 (41) ◽  
pp. 38589-38595 ◽  
Author(s):  
Sungjo Park ◽  
Oleksandr Gakh ◽  
Steven M. Mooney ◽  
Grazia Isaya
Keyword(s):  

1983 ◽  
Vol 5 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Jerzy Witwicki ◽  
Mankulathu V. Chidambaram ◽  
Earl Frieden
Keyword(s):  

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