Kinetics of Regulation

Lan, K. L., Zhong, H., Nanamori, M., and Neubig, R. R. (2000). Rapid kinetics of regulator of G-protein signaling (RGS)-mediated Gai and Gao deactivation. Galpha specificity of RGS4 and RGS7. /. Biol. Chem. 275, 33497-33503. 

Figure 3.6 Typical kinetics of regulated proteins following neurotrophin treatment of SYSY-TrkA or SYSY-TrkB. The majority of proteins like for instance galectin-1 were regulated in the late stimulation phase. Circles (control) and triangles (neurotrophin-treated) represent single standardized...

Luker KE, Smith MC, Luker GD, Gammon ST, Piwnica-Worms H, Piwnica-Worms D. Kinetics of regulated protein-protein interactions revealed with firefly luciferase complementation imaging in cells and living animals. Proc. Natl. Acad. Sci. U.S.A. 2004 101 12288-12293. 

Biochemical pathways consist of networks of individual reactions that have many feedback mechanisms. This makes their study and the elucidation of kinetics of individual reaction steps and their regulation so difficult. Nevertheless, important inroads have already been achieved. Much of this has been done by studying the metabolism of microorganisms in fermentation reactors. 

Inhibitors and retarders are used to stabilize monomers during storage or during processing (e.g, synthesis, distillation). They are often used to quench polymerization when a desired conversion has been achieved. They may also be used to regulate or control the kinetics of a polymerization process. 

Possible modes of regulation of filament assembly may be anticipated from the basic properties of actin. We have shown that the tightly bound divalent metal ion (Ca or Mg ) interacts with the P- and y-phosphates of ATP bound to actin, and that the Me-ATP bidentate chelate is bound to G-actin in the A configuration. The nature of the bound metal ion affects the conformation of actin, the binding kinetics of ATP and ADP, and the rate of ATP hydrolysis. 

In order to anticipate possible modes of regulation of cytoskeleton dynamics in vivo, it is necessary (a) to identify the kinetic intermediates involved in the polymerization process and to characterize their structural and functional properties and (b) to define the essential elementary steps in the hydrolysis process. 

Adelstein, R.S. Eisenberg, E. (1980). Regulation and kinetics of the actin-myosin-ATP interaction. Ann. Rev. Biochem. 49,921-956. 

The contractile apparatus may be thought of as the sum of those intracellular components which constitute the machinery of chemomechanical transduction. It is the set of proteins which convert the chemical energy of the terminal phosphate ester bond of ATP into mechanical work. The structure of the contractile apparatus is determined by the connections between the various protein molecules via specific binding sites or, in a minority of cases, via labile covalent linkages. The kinetics of the contractile machinery are determined by the regulation of changes in these connections. 

Lie WJ, Homburg CH, Kuijpers TW, Knol EF, Mul FR Roos D, Tool AT Regulation and kinetics of platelet-activating factor and leukotriene C4 synthesis by activated human basophils. Clin Exp Allergy 2003 33 1125-1134. 

To refer to the kinetics of allosteric inhibition as competitive or noncompetitive with substrate carries misleading mechanistic implications. We refer instead to two classes of regulated enzymes K-series and V-se-ries enzymes. For K-series allosteric enzymes, the substrate saturation kinetics are competitive in the sense that is raised without an effect on V. For V-series allosteric enzymes, the allosteric inhibitor lowers... 

Figure 49-14. Regulation of smooth muscle contraction by Ca. pL-myosin is the phosphorylated light chain of myosin L-myosin is the dephosphorylated light chain. (Adapted from Adelstein RS, Eisenberg R Regulation and kinetics of actin-myosin ATP interaction. Annu Rev Biochem 1980 49 921.)...

Kasai H (1999) Comparative biology of Ca -dependent exocytosis implications of kinetic diversity for secretory function. Trends Neurosci 22 88-93 Kasai H, Kishimoto T, Liu TT, Miyashita Y, Podini P, Grohovaz F, Meldolesi J (1999) Multiple and diverse forms of regulated exocytosis in wild-type and defective PC12 cells. Proc Natl... 

How to control the kinetics of the process, regulating the kinetics of two of the three cycles, to get only one rate determining cycle ... 

Ugarova N.N., Luciferase of Luciola mingrelica fireflies. Kinetics and regulation mechanism, J. Biolumin. Chemilumin. 1989 4 406-418. 

The subject of biochemical reactions is very broad, covering both cellular and enzymatic processes. While there are some similarities between enzyme kinetics and the kinetics of cell growth, cell-growth kinetics tend to be much more complex, and are subject to regulation by a wide variety of external agents. The enzymatic production of a species via enzymes in cells is inherently a complex, coupled process, affected by the activity of the enzyme, the quantity of the enzyme, and the quantity and viability of the available cells. In this chapter, we focus solely on the kinetics of enzyme reactions, without considering the source of the enzyme or other cellular processes. For our purpose, we consider the enzyme to be readily available in a relatively pure form, off the shelf, as many enzymes are. 

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