Document Detail

Physicochemical changes in phosphorylase kinase induced by its cationic activator Mg(2+).
MedLine Citation:
PMID:  23359552     Owner:  NLM     Status:  MEDLINE    
For over four decades free Mg(2+) ions, that is, those in excess of MgATP, have been reported to affect a wide variety of properties of phosphorylase kinase (PhK), including its affinity for other molecules, proteolysis, chemical crosslinking, phosphorylation, binding to certain monoclonal antibodies, and activity, which is stimulated. Additionally, for over three decades Mg(2+) has been known to act synergistically with Ca(2+) , another divalent activator of PhK, to affect even more properties of the enzyme. During all of this time, however, no study has been performed to determine the overall effects of free Mg(2+) ions on the physical properties of PhK, even though the effects of Ca(2+) ions on PhK's properties are well documented. In this study, changes in the physicochemical properties of PhK induced by Mg(2+) under nonactivating (pH 6.8) and activating (pH 8.2) conditions were investigated by circular dichroism spectroscopy, zeta potential analyses, dynamic light scattering, second derivative UV absorption, negative stain electron microscopy, and differential chemical crosslinking. The effects of the activator Mg(2+) on some of the properties of PhK measured by these techniques were found to be quite different at the two pH values, and displayed both differences and similarities with the effects previously reported to be induced by the activator Ca(2+) (Liu et al., Protein Sci 2008;17:2111-2119). The similarities may reflect the fact that both cations are activators, and foremost among their similarities is the dramatically less negative zeta potential induced by their binding to PhK.
Weiya Liu; Owen W Nadeau; Jessica Sage; Gerald M Carlson
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2013-02-21
Journal Detail:
Title:  Protein science : a publication of the Protein Society     Volume:  22     ISSN:  1469-896X     ISO Abbreviation:  Protein Sci.     Publication Date:  2013 Apr 
Date Detail:
Created Date:  2013-03-20     Completed Date:  2013-08-26     Revised Date:  2014-04-01    
Medline Journal Info:
Nlm Unique ID:  9211750     Medline TA:  Protein Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  444-54     Citation Subset:  IM    
Copyright Information:
Copyright © 2013 The Protein Society.
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MeSH Terms
Bicyclo Compounds / chemistry,  metabolism
Cations / chemistry,  metabolism
Circular Dichroism
Dinitrofluorobenzene / analogs & derivatives,  chemistry,  metabolism
Magnesium / chemistry*,  metabolism*
Phosphorylase Kinase / chemistry*,  metabolism*
Protein Conformation
Scattering, Radiation
Static Electricity
Grant Support
Reg. No./Substance:
0/Bicyclo Compounds; 0/Cations; 68654-25-1/dibromobimane; D241E059U6/Dinitrofluorobenzene; EC Kinase; G5VV4MQ22V/1,5-difluoro-2,4-dinitrobenzene; I38ZP9992A/Magnesium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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