Kinetic cycle

Fig. 6. Vectorial phosphorylation by a mechanism in which translocation and phosphorylation of the sugar are two distinct steps. The product binding site of the translocator T (domain C of II ") would be the substrate binding site of the kinase K (domains A and B). Since both the left-hand cycle and the right-hand cycle are catalyzed by the same enzyme they will very likely be kinetically dependent. Note that the kinetic cycle on the left-hand side of the figure is identical to Fig. 5.

These were lumped Into a much smaller number of pseudo components identified by carbon number and chemical nature. The lumps vary with the age of the catalyst. The table shows the 13 lumps adopted for the "start of kinetic cycle". The kinetic characteristics of these lumps are proprietary data. 

Figure 10. Three state kinetic cycle showing the relationship between three potential states A, B and C. The ki are rate constants.36...

Figure 11. Comparison of the ratio of the reactive correlation functions for two Hamiltonians, Ci(t)/C2(t), as a function of time t. Hamiltonian Hi is the model potential with y, = 0.1, y = 0.2. Hamiltonian H2 is the model potential with = 0.1, y = 0.3. The solid line is the computation with the kinetic cycle method the dotted line is the computation done in the conventional manner (running many trajectories with different initial conditions and counting how many are in region B at time t. 

Comparison of the efficiency of the calculation is provided in Fig. 12, in which we compare the rate of convergence for the two procedures. We estimate it as the number of energy evaluation that is required to reach desired error bars. The kinetic cycle is more efficient for the problem at hand by about two orders of magnitude. 

Figure 9. Steady-state kinetic cycle for the reduction of 7,8-DHF to 5,6,7,8-THF via DHFR.

The fact that these additional phosphorylations can affect the actin-activated MgATPase assay and not the in vitro motility assays is not problematic, as the two processes are probably limited by different steps in the kinetic cycle. The kinetic step that limits the actin-activated MgATPase assay is thought to be phosphate release or some step preceding phosphate release (Sellers, 1985). The rate of in vitro motility is thought to be regulated by ADP release (see Chapter 1, this volume). 

Similarly, in a triphasc membrane reaction, the overall kinetic cycle can be divided into two steps due to the presence of two practically insoluble liquid phases a chemical conversion step in which the active catalyst sites (Q with phcnolatc ions, Q PhO ) react with allyl bromide (RBr) to produce allyl phenyl ether (PhOR) and the other active catalyst site with Bf font ((/Br ), and an ion-exchange step in which the attached catalyst sites arc in contact with the aqueous phase in F.q 20. 

Hackney D.D. 1996. The kinetic cycles of myosin, kinesin, and dynein. Annu. Rev. Physiol. 58 ... 

As a matter of fact, an edge is not based on rate constants k) but on weights (tv) [17], which include the concentration of species not considered as intermediates of the cycle (namely, the reactants and products). The use of weights can simplify the solving of kinetic cycles. For instance, in the reaction... 

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