科研之友
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摘要
Preconditioning is the process of subjecting a cell or a tissue to a stimulus, with the result that the cell or the tissue becomes more tolerant to a second insult. The signalling machinery involved in preconditioning can be seen only as an ordered succession of enzymatic reactions. The fractal organization of the cytoplasm seems to be at present well proved. In classical chemical kinetics the rate constant of reaction is independent of time. However, recent studies have shown that the rate constant is time-dependent in many reactions. The main change is that the rate coefficient takes the following form: k(t) similar to k t(-h), 0 <= h <= 1. The kinetics of an enzymatic reaction was considered in a fractal-like environment A given time after the first stimulus, one returns to the initial conditions except that the change of the environment (the fractal dimension) which is conserved. At the second challenge the reaction rate is clearly less than at the first one. We conclude that inside cells the reaction kinetics is very well described by fractal-like kinetics and that this type of enzyme kinetics may explain at least in part the preconditioning effect.
- 出版日期2011-7
