细胞内一次与二次共价修饰的特异性比较  

Comparison of Specificity Induced by One and Dual Covalent Modifications

作　　者：张露萍[1] 赵刚[1] 

机构地区：[1]江西蓝天学院复杂生命动力学研究所

出　　处：《江西蓝天学院学报》2010年第4期22-27,共6页Journal of Jiangxi Blue Sky University

摘　　要：共价修饰参与了细胞内由各种各样的生化反应构成的信号通路。人们曾用确定性方法研究得到二次共价修饰的特异性比一次的好的结论,那么该结论在随机系统是否也成立,至今没有明确的答案。针对这一问题,本文研究了一个受到瞬态刺激、少数分子参与反应的随机系统,考察系统的动力学,比较其经历一次与二次共价修饰的特异性。结果表明,在某些生理条件下,参与反应的分子数少到一定程度时,系统在经历二次共价修饰的特异性会比一次的更差,当然这样的分子数范围是允许的。此外,本文还研究了刺激的强度和时程、以及共价修饰上游反应速率等几个可能影响到特异性的因素,研究发现,上述因素都会影响随机系统中一次与二次共价修饰的特异性比较。结论：刺激弱且短暂,或共价修饰上游活化速率相对失活速率慢,会使得上述随机系统在经历一次共价修饰的特异性比经历二次的好。Covalent modifications are required in many signaling pathways.It has been discussed from a deterministic viewpoint that dual covalent modification is more favorable than single covalent modification for signaling specificity.However,whether this conclusion is feasible in stochastic situation has not been studied.To study the role of covalent modifications in a stochastic signaling pathway,we here simulate the dynamics of a transiently stimulated signaling pathway,considering the influence of the stochasticity arising from the low molecule number of reactants.It turns out that the specificity of dual covalent modification would be worse than that of single covalent modification when the number of molecules is in some biologically plausible range.We further discuss some factors that have potential influence on specificity,such as the rates of the upstream reaction cycle of the covalent modifications,the duration and the magnitude of the transient stimulus.Our numerical results indicate that these factors indeed affect specificity.Conclusion：superiority of single covalent modification in specificity would arise from weak and transient stimuli as well as an upstream reaction whose activation rate is slow while deactivation rate is fast.

关 键 词：共价修饰 特异性 信号转导 瞬态刺激 

分 类 号：O18[理学—数学]