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Title: A sup 31 P NMR study of mitochondrial inorganic phosphate visibility: Effects of Ca sup 2+ , Mn sup 2+ , and the pH gradient

Abstract

The effects of external pH, temperature, and Ca{sup 2+} and Mn{sup 2+} concentrations on the compartmentation and NMR visibility of inorganic phosphate (P{sub i}) were studied in isolated rat liver mitochondria respiring on succinate and glutamate. Mitochondrial matrix P{sub i} is totally visible by NMR at 8C and at low external concentrations of P{sub i}. However, when the external P{sub i} concentration is increased above 7 mM, the pH gradient decreases, the amount of matrix P{sub i} increases, and the fraction not observed by NMR increases. Raising the temperature to 25C also decreases the pH gradient and the P{sub i} fraction observed by NMR. At physiologically relevant concentrations, Ca{sup 2+} and Mn{sup 2+} do not seem to play a major role in matrix P{sub i} NMR invisibility. For Ca{sup 2+} concentrations above 30 nmol/mg of protein, formation of insoluble complexes will cause loss of P{sub i} signal intensity. For Mn{sup 2+} concentrations above 2 nmol/mg of protein, the P{sub i} peak can be broadened sufficiently to preclude detection of a high-resolution signal. The results indicate that mitochondrial matrix P{sub i} should be mostly observable up to 25C by high-resolution NMR. While the exact nature of the NMR-invisible phosphate in perfusedmore » or in vivo liver is yet to be determined, better success at detecting and resolving both P{sub i} pools by NMR is indicated at high field, low temperature, and optimized pulsing conditions.« less

Authors:
; ; ; ;  [1]
  1. Pennsylvania State Univ., Hershey (United States)
Publication Date:
OSTI Identifier:
5559733
Resource Type:
Journal Article
Journal Name:
Biochemistry; (United States)
Additional Journal Information:
Journal Volume: 31:5; Journal ID: ISSN 0006-2960
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; PHOSPHATES; NUCLEAR MAGNETIC RESONANCE; MANGANESE COMPOUNDS; MITOCHONDRIA; PH VALUE; PHOSPHORUS 31; TEMPERATURE DEPENDENCE; CELL CONSTITUENTS; ISOTOPES; LIGHT NUCLEI; MAGNETIC RESONANCE; NUCLEI; ODD-EVEN NUCLEI; OXYGEN COMPOUNDS; PHOSPHORUS COMPOUNDS; PHOSPHORUS ISOTOPES; RESONANCE; STABLE ISOTOPES; TRANSITION ELEMENT COMPOUNDS; 550201* - Biochemistry- Tracer Techniques

Citation Formats

Hutson, S M, Williams, G D, Berkich, D A, LaNoue, K F, and Briggs, R W. A sup 31 P NMR study of mitochondrial inorganic phosphate visibility: Effects of Ca sup 2+ , Mn sup 2+ , and the pH gradient. United States: N. p., 1992. Web. doi:10.1021/bi00120a007.
Hutson, S M, Williams, G D, Berkich, D A, LaNoue, K F, & Briggs, R W. A sup 31 P NMR study of mitochondrial inorganic phosphate visibility: Effects of Ca sup 2+ , Mn sup 2+ , and the pH gradient. United States. https://doi.org/10.1021/bi00120a007
Hutson, S M, Williams, G D, Berkich, D A, LaNoue, K F, and Briggs, R W. 1992. "A sup 31 P NMR study of mitochondrial inorganic phosphate visibility: Effects of Ca sup 2+ , Mn sup 2+ , and the pH gradient". United States. https://doi.org/10.1021/bi00120a007.
@article{osti_5559733,
title = {A sup 31 P NMR study of mitochondrial inorganic phosphate visibility: Effects of Ca sup 2+ , Mn sup 2+ , and the pH gradient},
author = {Hutson, S M and Williams, G D and Berkich, D A and LaNoue, K F and Briggs, R W},
abstractNote = {The effects of external pH, temperature, and Ca{sup 2+} and Mn{sup 2+} concentrations on the compartmentation and NMR visibility of inorganic phosphate (P{sub i}) were studied in isolated rat liver mitochondria respiring on succinate and glutamate. Mitochondrial matrix P{sub i} is totally visible by NMR at 8C and at low external concentrations of P{sub i}. However, when the external P{sub i} concentration is increased above 7 mM, the pH gradient decreases, the amount of matrix P{sub i} increases, and the fraction not observed by NMR increases. Raising the temperature to 25C also decreases the pH gradient and the P{sub i} fraction observed by NMR. At physiologically relevant concentrations, Ca{sup 2+} and Mn{sup 2+} do not seem to play a major role in matrix P{sub i} NMR invisibility. For Ca{sup 2+} concentrations above 30 nmol/mg of protein, formation of insoluble complexes will cause loss of P{sub i} signal intensity. For Mn{sup 2+} concentrations above 2 nmol/mg of protein, the P{sub i} peak can be broadened sufficiently to preclude detection of a high-resolution signal. The results indicate that mitochondrial matrix P{sub i} should be mostly observable up to 25C by high-resolution NMR. While the exact nature of the NMR-invisible phosphate in perfused or in vivo liver is yet to be determined, better success at detecting and resolving both P{sub i} pools by NMR is indicated at high field, low temperature, and optimized pulsing conditions.},
doi = {10.1021/bi00120a007},
url = {https://www.osti.gov/biblio/5559733}, journal = {Biochemistry; (United States)},
issn = {0006-2960},
number = ,
volume = 31:5,
place = {United States},
year = {Tue Feb 11 00:00:00 EST 1992},
month = {Tue Feb 11 00:00:00 EST 1992}
}