AMP deaminase reaction as a control system of glycolysis in yeast. Role of ammonium ion in the interaction of phosphofructokinase and pyruvate kinase activity with the adenylate energy charge.

1. The modification of pyruvate kinase activity in vitro was examined by altering the environmental [Mg2+]/[Ca2+] ratio with EDTA on the one hand and isolated rat liver mitochondria on the other. 2. Controlled additions of Ca2+ and EDTA caused pyruvate kinase activity to be alternately and rapidly switched on and off. 3. By being able to accumulate Ca2+ in preference to Mg2+ rat liver mitochondria were able to alter the [Mg2+]/[Ca2+] ratio in the vicinity of pyruvate kinase and thereby modify the activity of this enzyme. 4. The possible role of mitochondria in modifying pyruvate kinase and other ion-sensitive cytoplasmic enzyme activities is discussed.

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Red blood cell age, pyruvate kinase activity, and insulin receptors. Evidence that monocytes and RBCs may behave differently

Diabetes ◽

10.2337/diabetes.32.11.1017 ◽

1983 ◽

Vol 32 (11) ◽

pp. 1017-1022 ◽

Cited By ~ 5

Author(s):

A. Camagna ◽

R. De Pirro ◽

L. Tardella ◽

L. Rossetti ◽

R. Lauro ◽

...

Keyword(s):

Blood Cell ◽

Pyruvate Kinase ◽

Red Blood Cell ◽

Kinase Activity ◽

Insulin Receptors ◽

Pyruvate Kinase Activity ◽

Cell Age

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Red Blood Cell Age, Pyruvate Kinase Activity, and Insulin Receptors: Evidence that Monocytes and RBCs May Behave Differently

Diabetes ◽

10.2337/diab.32.11.1017 ◽

1983 ◽

Vol 32 (11) ◽

pp. 1017-1022 ◽

Cited By ~ 5

Author(s):

A. Camagna ◽

R. D. Pirro ◽

L. Tardella ◽

L. Rossetti ◽

R. Lauro ◽

...

Keyword(s):

Blood Cell ◽

Pyruvate Kinase ◽

Red Blood Cell ◽

Kinase Activity ◽

Insulin Receptors ◽

Pyruvate Kinase Activity ◽

Cell Age

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Control of AMP deaminase 1 binding to myosin heavy chain

AJP Cell Physiology ◽

10.1152/ajpcell.1998.275.3.c870 ◽

1998 ◽

Vol 275 (3) ◽

pp. C870-C881 ◽

Cited By ~ 59

Author(s):

Ichiro Hisatome ◽

Takayuki Morisaki ◽

Hiroshi Kamma ◽

Takako Sugama ◽

Hiroko Morisaki ◽

...

Keyword(s):

Myosin Heavy Chain ◽

Heavy Chain ◽

Sequence Similarity ◽

Critical Role ◽

Energy Charge ◽

Adenylate Energy Charge ◽

Amp Deaminase ◽

Amino Terminal

AMP deaminase (AMPD) plays a central role in preserving the adenylate energy charge in myocytes following exercise and in producing intermediates for the citric acid cycle in muscle. Prior studies have demonstrated that AMPD1 binds to myosin heavy chain (MHC) in vitro; binding to the myofibril varies with the state of muscle contraction in vivo, and binding of AMPD1 to MHC is required for activation of this enzyme in myocytes. The present study has identified three domains in AMPD1 that influence binding of this enzyme to MHC using a cotransfection model that permits assessment of mutations introduced into the AMPD1 peptide. One domain that encompasses residues 178–333 of this 727-amino acid peptide is essential for binding of AMPD1 to MHC. This region of AMPD1 shares sequence similarity with several regions of titin, another MHC binding protein. Two additional domains regulate binding of this peptide to MHC in response to intracellular and extracellular signals. A nucleotide binding site, which is located at residues 660–674, controls binding of AMPD1 to MHC in response to changes in intracellular ATP concentration. Deletion analyses demonstrate that the amino-terminal 65 residues of AMPD1 play a critical role in modulating the sensitivity to ATP-induced inhibition of MHC binding. Alternative splicing of the AMPD1 gene product, which alters the sequence of residues 8–12, produces two AMPD1 isoforms that exhibit different MHC binding properties in the presence of ATP. These findings are discussed in the context of the various roles proposed for AMPD in energy production in the myocyte.

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