skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Metal ion effects on enolase activity

Abstract

Most metal binding studies with yeast enolase suggest that two metals per monomer are required for catalytic activity. The functions of metal I and metal II have not been unequivocally defined. In a series of kinetic experiments where the concentration of MgII is kept constant at subsaturating levels (1mM), the addition of MnII or of ZnII gives a hyperbolic decrease in activity. The final velocity of these mixed metal systems is the same velocity obtained with either only MnII or ZnII respectively. The concentration of MnII (40 ..mu..M) or of Zn (2..mu..M) which gives half maximal effect in the presence of (1mM) MgII is approximately the same as the Km' value for MnII (9..mu..M) or ZnII (3..mu..M) respectively. Direct binding of MnII to enolase in the absence and presence of MgII shows that MnII and MgII compete for the same metal site on enolase. In the presence of 2-phosphoglycerate (2-PGA) and MgII, only a single site is occupied by MnII. Results suggest MnII at site I and MgII at site II. PRR and high resolution /sup 1/H and /sup 31/P NMR studies of enzyme-ligand complexes containing MnII and MgII and MnII are consistent with this model. /sub 31/P measurements allowmore » a measure of the equilibrium constant (0.36) for enolase. Saturation transfer measurements yield net rate constants (k/sub f/ = 0.49s/sup -1/; k/sub r/ = 1.3s/sup -1/) for the overall reaction. These values are smaller than k/sub cat/ (38s/sup -1/) measured under analogous conditions. The cation at site I appears to determine catalytic activity.« less

Authors:
;
Publication Date:
Research Org.:
Univ. of Notre Dame, IN
OSTI Identifier:
5325222
Report Number(s):
CONF-8606151-
Journal ID: CODEN: FEPRA
Resource Type:
Conference
Journal Name:
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
Additional Journal Information:
Journal Volume: 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; 59 BASIC BIOLOGICAL SCIENCES; 62 RADIOLOGY AND NUCLEAR MEDICINE; CARBON-OXYGEN LYASES; ENZYME ACTIVITY; MAGNESIUM; BIOCHEMICAL REACTION KINETICS; BIOLOGICAL EFFECTS; MANGANESE; ZINC; NMR SPECTRA; NUCLEAR MAGNETIC RESONANCE; PHOSPHORUS 31; YEASTS; ALKALINE EARTH METALS; ELEMENTS; ENZYMES; FUNGI; ISOTOPES; KINETICS; LIGHT NUCLEI; LYASES; MAGNETIC RESONANCE; METALS; MICROORGANISMS; NUCLEI; ODD-EVEN NUCLEI; PHOSPHORUS ISOTOPES; PLANTS; REACTION KINETICS; RESONANCE; SPECTRA; STABLE ISOTOPES; TRANSITION ELEMENTS; 560302* - Chemicals Metabolism & Toxicology- Microorganisms- (-1987); 550201 - Biochemistry- Tracer Techniques; 550600 - Medicine

Citation Formats

Lee, M E, and Nowak, T. Metal ion effects on enolase activity. United States: N. p., 1986. Web.
Lee, M E, & Nowak, T. Metal ion effects on enolase activity. United States.
Lee, M E, and Nowak, T. 1986. "Metal ion effects on enolase activity". United States.
@article{osti_5325222,
title = {Metal ion effects on enolase activity},
author = {Lee, M E and Nowak, T},
abstractNote = {Most metal binding studies with yeast enolase suggest that two metals per monomer are required for catalytic activity. The functions of metal I and metal II have not been unequivocally defined. In a series of kinetic experiments where the concentration of MgII is kept constant at subsaturating levels (1mM), the addition of MnII or of ZnII gives a hyperbolic decrease in activity. The final velocity of these mixed metal systems is the same velocity obtained with either only MnII or ZnII respectively. The concentration of MnII (40 ..mu..M) or of Zn (2..mu..M) which gives half maximal effect in the presence of (1mM) MgII is approximately the same as the Km' value for MnII (9..mu..M) or ZnII (3..mu..M) respectively. Direct binding of MnII to enolase in the absence and presence of MgII shows that MnII and MgII compete for the same metal site on enolase. In the presence of 2-phosphoglycerate (2-PGA) and MgII, only a single site is occupied by MnII. Results suggest MnII at site I and MgII at site II. PRR and high resolution /sup 1/H and /sup 31/P NMR studies of enzyme-ligand complexes containing MnII and MgII and MnII are consistent with this model. /sub 31/P measurements allow a measure of the equilibrium constant (0.36) for enolase. Saturation transfer measurements yield net rate constants (k/sub f/ = 0.49s/sup -1/; k/sub r/ = 1.3s/sup -1/) for the overall reaction. These values are smaller than k/sub cat/ (38s/sup -1/) measured under analogous conditions. The cation at site I appears to determine catalytic activity.},
doi = {},
url = {https://www.osti.gov/biblio/5325222}, journal = {Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)},
number = ,
volume = 45:6,
place = {United States},
year = {Thu May 01 00:00:00 EDT 1986},
month = {Thu May 01 00:00:00 EDT 1986}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: