title: 31P NMR studies of creatine kinase flux in M-creatine kinase-deficient mouse heart.
abstract: Hearts of wild-type and cytosolic muscle creatine kinase (M-CK)-knockout mice were perfused with Krebs-Henseleit buffer containing 10 mM glucose and 5 mM pyruvate and studied during pacing at 400 and 600 beats/min and during K+ arrest. Phosphocreatine (PCr) and ATP concentrations in M-CK-deficient hearts were not significantly different from those in wild-type hearts. With the use of 31P NMR saturation transfer, the flux mediated predominantly by mitochondrial creatine kinase (Mi-CK) was clearly detected in M-CK-deficient hearts. Mi-CK flux was 4.8 +/- 0.6 and 4.5 +/- 0.6 mM/s during pacing at 400 and 600 beats/min, respectively, and was 3. 5 +/- 0.4 mM/s during cardiac arrest. In control hearts total CK flux was 7.8 +/- 1.1 and 6.6 +/- 1.3 mM/s during pacing at 400 and 600 beats/min, respectively, and decreased to 3.8 +/- 0.5 mM/s during arrest. It is suggested that the relative contribution of Mi-CK to the total NMR-measured CK flux in the wild-type heart is higher than that of the homodimeric M-CK isoform (MM-CK).
authors.affiliation: Department of In Vivo NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, NL-3584 CJ Utrecht, The Netherlands.
authors.forename: F A
authors.initials: FA
authors.lastname: Van Dorsten
authors.forename: M G
authors.initials: MG
authors.lastname: Nederhoff
authors.forename: K
authors.initials: K
authors.lastname: Nicolay
authors.forename: C J
authors.initials: CJ
authors.lastname: Van Echteld
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003402:Creatine Kinase / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*; D006339:Heart Rate; D066298:In Vitro Techniques; D007527:Isoenzymes; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D010758:Phosphorus
chemical_list: D007527:Isoenzymes; D010725:Phosphocreatine; D010758:Phosphorus; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D003402:Creatine Kinase