Linked Life Data

7636446

Source:http://linkedlifedata.com/resource/pubmed/id/7636446

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 8
pubmed:dateCreated
1995-9-14
pubmed:abstractText
Physiologists and biochemists frequently ignore the importance of adjusting equilibrium constants to the ionic conditions of the cell prior to calculating a number of bioenergetic and kinetic parameters. The present study examines the effect of pH and free magnesium levels (free [Mg2+]) on the apparent equilibrium constants (K') of creatine kinase (ATP: creatine N-phosphotransferase; EC 2.7.3.2), adenylate kinase (ATP:AMP phosphotransferase; EC 2.7.4.3) and adenosinetriphosphatase (ATP phosphohydrolase; EC 3.6.1.3) reactions. We show how K' can be calculated using the equilibrium constant of a specified chemical reaction (Kref) and the appropriate acid-dissociation and Mg(2+)-binding constants at an ionic strength (I) of 0.25 mol l-1 and 38 degrees C. Substituting the experimentally determined intracellular pH and free [Mg2+] into the equation containing a known Kref and two variables, pH and free [Mg2+], enables K' to be calculated at the experimental ionic conditions. Knowledge of K' permits calculation of cytosolic phosphorylation ratio ([ATP]/[ADP][Pi]), cytosolic free [ADP], free [AMP], standard transformed Gibbs energy of formation (delta fG' degrees ATP) and the transformed Gibbs energy of the system (delta fG' ATP) for the biological system. Such information is vital for the quantification of organ and tissue bioenergetics under physiological and pathophysiological conditions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-0949
pubmed:author
pubmed:issnType
Print
pubmed:volume
198
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1775-82
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Adjustment of K' to varying pH and pMg for the creatine kinase, adenylate kinase and ATP hydrolysis equilibria permitting quantitative bioenergetic assessment.
pubmed:affiliation
Department of Molecular Sciences, James Cook University of North Queensland, Townsville, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't