AJP - Endo Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Endocrinol Metab 262: E344-E352, 1992;
0193-1849/92 $5.00
This Article
Right arrow Full Text (PDF)
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 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 Google Scholar
Google Scholar
Right arrow Articles by Kim, Y. A.
Right arrow Articles by Passonneau, J. V.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kim, Y. A.
Right arrow Articles by Passonneau, J. V.

AJP - Endocrinology and Metabolism, Vol 262, Issue 3 E344-E352, Copyright © 1992 by American Physiological Society

ARTICLES

Regulation of the purine salvage pathway in rat liver

Y. A. Kim, M. T. King, W. E. Teague Jr, G. A. Rufo Jr, R. L. Veech and J. V. Passonneau
Laboratory of Metabolism and Molecular Biology, National Institute of Alcohol Abuse and Alcoholism, Rockville, Maryland 20852.

The regulation of purine metabolism in rat liver has been examined under conditions that alter the flux through the pathway. Rats were given intraperitoneal injections of ethanol, sodium acetate, or sodium phosphate to attain body water concentrations of approximately 70, 20, and 10 mM, respectively. The livers were freeze-clamped after 30 min, and extracts were made for the analysis of metabolites, cofactors, purine bases, and nucleosides; homogenates were made for the measurement of the activities and kinetic parameters of seven enzymes that participate in purine salvage. The values of the equilibrium constants of nine reactions were determined in vitro and compared with the ratios of the reactants measured in liver. The changes in phosphoribosylpyrophosphate (PRPP), a key intermediate in both the de novo and salvage pathways of purine metabolism, were directly correlated with the changes in ribose 5-phosphate (ribose-5-P); ([PRPP] = 1.7[ribose-5-P] - 7.4 mumol/kg). Ribose-5-P concentrations in turn could be predicted from the liver content of fructose 6-phosphate and glyceraldehyde 3-phosphate by calculation from the known equilibria. The maximum velocities in the tissue of the seven enzymes measured were calculated from the measured substrate values in the liver and with consideration of other effectors of enzyme activity. PRPP synthetase was the least active of the enzymes measured, indicating a possible rate-limiting step. The delta G of the enzyme steps differed from equilibrium values by factors ranging from 4 (nucleoside phosphorylase) to 10(5) (PRPP synthetase and purine transferase reactions). The regulation of purine salvage appeared to depend on the levels of PRPP and ribose-5-P.


This article has been cited by other articles:


Home page
 J. Appl. Physiol.Home page
J. J. Brault and R. L. Terjung
Purine salvage to adenine nucleotides in different skeletal muscle fiber types
J Appl Physiol, July 1, 2001; 91(1): 231 - 238.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
S. Zhao, R. J. Snow, C. G. Stathis, M. A. Febbraio, and M. F. Carey
Muscle adenine nucleotide metabolism during and in recovery from maximal exercise in humans
J Appl Physiol, May 1, 2000; 88(5): 1513 - 1519.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
T. Kawaguchi, R. L. Veech, and K. Uyeda
Regulation of Energy Metabolism in Macrophages during Hypoxia. ROLES OF FRUCTOSE 2,6-BISPHOSPHATE AND RIBOSE 1,5-BISPHOSPHATE
J. Biol. Chem., July 20, 2001; 276(30): 28554 - 28561.
[Abstract] [Full Text] [PDF]


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