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Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/10054/3332

Title: Reducing agents mitigate protein synthesis inhibition mediated by vanadate and vanadyl compounds in reticulocyte lysates
Authors: KRISHNAMOORTHY, T
SREEDHARA, A
RAO, CP
RAMAIAH, KVA
Keywords: guanine-nucleotide-exchange
initiation factor-ii
heavy-metal ions
oxidized glutathione
glycogen-synthase
reversing factor
blood-glucose
diabetic rats
alpha-subunit
phosphorylation
Issue Date: 1998
Publisher: ACADEMIC PRESS INC
Citation: ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 349(1), 122-128
Abstract: Recently, we synthesized and characterized vanadyl saccharides to evaluate the effects of various vanadate and vanadyl complexes, which differ in their oxidation states on various biomacromolecules and cellular activities (1, 2). Here, we report that both vanadate (+V oxidation state) and different vanadyl species (+IV oxidation state) such as vanadyl D-glucose, vanadyl diascorbate, and vanadyl sulfate, impair the formation of polysomes and inhibit the initiation of protein synthesis in hemin-supplemented rabbit reticulocyte lysates. Vanadate inhibits protein synthesis more severely than vanadyl species and is consistent with the idea that vanadate is reduced to vanadyl state intracellularly. The inhibition of protein synthesis caused by low concentrations (10-20 mu M) of vanadate and vanadyl species is effectively mitigated by reducing agents such as dithiothreitol, reduced glutathione (GSH), or reduced pyridine dinucleotide, A significant decrease in the protein synthesis inhibition in vanadate-treated lysates by GSH suggests that the mechanism of protein synthesis inhibition by vanadate is different than the action of other oxidants such as heavy metal ions and oxidized glutathione, This suggestion is also consistent with the findings that vanadium compounds do not stimulate phosphorylation of the alpha (alpha) subunit of initiation factor 2 (eIF2) or decrease the guanine nucleotide exchange activity of eIF2B, which is required to exchange GDP for GTP in eIF2.GDP binary complex. The reduction of vanadate to vanadyl state and the subsequent complex formation of vanadyl species with the endogenous reducing compounds or with the -SH groups of certain proteins may be the cause for protein synthesis inhibition in lysates. (C) 1998
URI: http://dx.doi.org/10.1006/abbi.1997.0394
http://dspace.library.iitb.ac.in/xmlui/handle/10054/3332
http://hdl.handle.net/10054/3332
ISSN: 0003-9861
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