Current Topics in Cellular Regulation

Current Topics in Cellular Regulation: Volume 23 is a collection of papers that discusses pyruvate carboxylase, the regulation of carbohydrate metabolism, and the plasma membrane ATPase of fungi or plants. Other papers deal with adrenergic control of phosphofructokinase, protein phosphatase, as well as the regulation of polypeptide precursors of mature mitochondrial proteins. One paper explains the three dimensional structure of pyruvate carboxylase and its reaction mechanism. Electron microscopic analyses show that four monomers of pyruvate carboxylases isolated from vertebrate sources form a tight tetrahedron-like structure. Another paper describes the regulation of fructose 2,6-bisphosphate concentration in the liver and of the enzymes that are responsible for its metabolism, and the mechanism involved in fructose, particularly in the regulation of 6-phosphofructo-1-kinase and fructose-1,6-bisphosphatase activity. The paper also explains the role of this effector in the regulation of hepatic carbohydrate metabolism. One paper deals with the different levels of biological organization (whole cells, isolated plasma membranes, and purified enzyme) that characterizes the plasma membrane ATPase of fungi and plants as a novel type of proton pump. The collection can prove useful for biologists, microbiologists, students, and professors of biology and biophysics.

Contenu

Contributors
Pyruvate Carboxylase
I. Introduction
II. Structural Studies
III. Studies on the Mechanism of Action
IV. Carboxylation of Biotin
V. Translocation of Biotin Between the Two Subsites
VI. Carboxylation of Pyruvate
VII. Detailed Description of the Steady-State Mechanism
VIII. Participation of the Allosteric Activator Acetyl-CoA
IX. Conclusion
References
The Role of Fructose 2,6-Bisphosphate in the Regulation of Carbohydrate Metabolism
I. Introduction
II. Discovery and Identification of Fructose 2,6-P2
III. Regulation of Fructose 2,6-P2 Levels
IV. Regulation of Enzyme Activity by Fructose 2,6-P2
V. Regulation of Hepatic Carbohydrate Metabolism by Fructose 2,6-P2
References
Plasma Membrane ATPase of Fungi and Plants as a Novel Type of Proton Pump
I. Introduction
II. In Vivo Studies on the Proton Pumps of Fungi and Plants
III. ATPase and Proton Transport in Isolated Plasma Membranes
IV. Purification and Reconstitution of the Proton-Pumping ATPase
V. Conclusions and Perspectives
References
Adrenergic Control of Phosphofructokinase and Glycolysis in Rat Heart
I. Introduction
II. Adrenergic Regulation of PFK in Liver and Muscle
III. Properties of the Epinephrine-Activated Form of Heart PFK
IV. Adrenergic Receptors Involved in the Activation of Heart PFK
V. Molecular Mechanisms
VI. Deactivase
VII. The Role of Adrenergic Control of PFK in Cardiac Glycolysis
VIII. Obesity and the Adrenergic Regulation of Cardiac PFK and Glucose Metabolism
IX. The Functional Significance of Adrenergic Control of PFK and Glucose Uptake
References
Regulation of ATP-Mg-Dependent Protein Phosphatase
I. Introduction
II. Protein Kinases and Phosphatases in Glycogen Metabolism
III. Protein Components Involved in the Regulation of the Multisubstrate Protein Phosphatase
IV. Characterization of the ATP-Mg-Dependent Multisubstrate Protein Phosphatase
V. Integration of Protein Phosphatase Activity in the Hormonal and Metabolic Regulation of Glycogen Metabolism
VI. Concluding Remarks
References
Transport and Regulation of Polypeptide Precursors of Mature Mitochondrial Proteins
I. Introduction
II. The Dual Origin of Mitochondrial Proteins
III. Protein Transport Across Membranes in Biological Systems
IV. Protein Transport from Cytosol to Mitochondria
V. Enzymatic Activity of Protein Precursors
VI. Concluding Remarks
References
Index
Cumulative Contributors Index
Contents of Previous Volumes