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Basal glycogenolysis in mouse skeletal muscle: in vitro model predicts in vivo fluxesA previously published mammalian kinetic model of skeletal muscle glycogenolysis, consisting of literature in vitro parameters, was modified by substituting mouse specific Vmax values. The model demonstrates that glycogen breakdown to lactate is under ATPase control. Our criteria to test whether in vitro parameters could reproduce in vivo dynamics was the ability of the model to fit phosphocreatine (PCr) and inorganic phosphate (Pi) dynamic NMR data from ischemic basal mouse hindlimbs and predict biochemically-assayed lactate concentrations. Fitting was accomplished by optimizing four parameters--the ATPase rate coefficient, fraction of activated glycogen phosphorylase, and the equilibrium constants of creatine kinase and adenylate kinase (due to the absence of pH in the model). The optimized parameter values were physiologically reasonable, the resultant model fit the [PCr] and [Pi] timecourses well, and the model predicted the final measured lactate concentration. This result demonstrates that additional features of in vivo enzyme binding are not necessary for quantitative description of glycogenolytic dynamics.
Document ID
20040088102
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Lambeth, Melissa J.
(University of Washington, Department of Bioengineering Seattle 98195-7115, United States)
Kushmerick, Martin J.
Marcinek, David J.
Conley, Kevin E.
Date Acquired
August 21, 2013
Publication Date
January 1, 2002
Publication Information
Publication: Molecular biology reports
Volume: 29
Issue: 1-2
ISSN: 0301-4851
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Musculoskeletal

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