Kushmerick M J
Department of Radiology, University of Washington, Seattle 98195, USA.
Am J Physiol. 1997 May;272(5 Pt 1):C1739-47. doi: 10.1152/ajpcell.1997.272.5.C1739.
The multiple ionic forms of metabolites were evaluated at 37 degrees C for four reactions important in muscle contraction and recovery: 1) ATPase, 2) creatine kinase, 3) the Lohmann reaction, and 4) the Lohmann reaction reversed by coupling to glycogenolysis and glycolysis. Solution of the system of equations defining the multiple equilibria of the proton and cation complexes gives the concentration of each ionic form and a value for the proton stoichiometry for each reaction. The proton stoichiometric coefficients are unique for each reaction and are a function of pH because of differential binding of Mg2+ and K+ to adenine nucleotides, phosphocreatine, and Pi and because of different acidic dissociation constants for the metabolites. These results show the need to consider the binding of K+ in addition to the previously documented effects of Mg2+ in the cytoplasmic milieu. Commercially available software was used to show that related problems can be calculated readily on personal computers in applications similar to those described here.
在37摄氏度下，对肌肉收缩和恢复过程中重要的四个反应的代谢物多种离子形式进行了评估：1）ATP酶，2）肌酸激酶，3）洛曼反应，以及4）通过与糖原分解和糖酵解偶联而逆转的洛曼反应。定义质子和阳离子络合物多重平衡的方程组的解给出了每种离子形式的浓度以及每个反应的质子化学计量值。质子化学计量系数对于每个反应都是唯一的，并且由于Mg2+和K+与腺嘌呤核苷酸、磷酸肌酸和Pi的差异结合以及代谢物不同的酸解离常数，它是pH的函数。这些结果表明，除了先前记录的Mg2+在细胞质环境中的作用外，还需要考虑K+的结合。使用市售软件表明，类似此处所述的应用中，相关问题可以在个人计算机上轻松计算出来。
