Am J Physiol Cell Physiol Watch the video to learn how APS reaches out to developing nations.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 283: C743-C751, 2002. First published May 1, 2002; doi:10.1152/ajpcell.00101.2002
0363-6143/02 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
283/3/C743    most recent
00101.2002v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (9)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kongas, O.
Right arrow Articles by Krab, K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kongas, O.
Right arrow Articles by Krab, K.
Vol. 283, Issue 3, C743-C751, September 2002

High Km of oxidative phosphorylation for ADP in skinned muscle fibers: where does it stem from?

Olav Kongas1,2, Tai L. Yuen3, Marijke J. Wagner3, Johannes H. G. M. van Beek3, and Klaas Krab3

1 Laboratory for Physiology, Institute for Cardiovascular Research, Vrije Universiteit Medical Center 1081 BT Amsterdam; 3 Faculty of Earth and Life Sciences, Department of Molecular Cell Physiology, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; and 2 Department of Mechanics and Applied Mathematics, Institute of Cybernetics, Tallinn Technical University, 12618 Tallinn, Estonia

Mitochondria in saponin-skinned cardiac fiber bundles were reported to have an order of magnitude lower apparent affinity to ADP than isolated mitochondria. Although ADP was measured outside the bundles, it was thought that the low affinity was not caused by diffusion gradients because of relatively short diffusion distances. Here we test the hypothesis that considerable ADP diffusion gradients exist and can be diminished by increasing the intrafiber ADP production rate. We increased the ADP-producing activity in rat heart skinned fiber bundles by incubating with 100 IU/ml yeast hexokinase and glucose. Consequently, we observed a significant decrease of the apparent Michaelis constant (Km) to ADP of the respiration rate of bundles from 216 ± 59 to 50 ± 9 µM. Fitting the results with a mathematical model, we estimated the Km of mitochondria in the bundles to be 25 µM. We conclude that the affinity to ADP of in situ mitochondria in heart is of the same order of magnitude as that of isolated mitochondria.

mitochondria; heart; soleus; adenosine triphosphatase; diffusion; Michaelis constant; adenosine 5'-triphosphate


This article has been cited by other articles:


Home page
 Am. J. Physiol. Cell Physiol.Home page
J. H. G. M. van Beek
Adenine nucleotide-creatine-phosphate module in myocardial metabolic system explains fast phase of dynamic regulation of oxidative phosphorylation
Am J Physiol Cell Physiol, September 1, 2007; 293(3): C815 - C829.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online