期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1993
卷号：90
期号：11
页码：5148-5152
DOI：10.1073/pnas.90.11.5148
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The transient behavior of muscle in double-or multiple-step length perturbations [Lombardi, V., Piazzesi, G. & Linari, M. (1992) Nature (London) 355, 638-641] is simulated with a "conventional" cross-bridge model, which has been reported [Eisenberg, E., Hill, T. L. & Chen, Y. (1980) Biophys. J. 29, 195-227] to account for many mechanical, as well as biochemical, muscle data. The quick recovery of tension after double- or multiple-length perturbations was calculated for the model without any readjustment of its original parameters. The regeneration rate of the quick tension recovery of the model is fast and comparable to that measured experimentally by Lombardi et al. For multiple-step "stair-case"-type length releases, the tension response reaches a steady-state shape after three or four steps, and the average ATP turnover is much slower than the regeneration of the quick tension recovery. Our simulation shows that the experimental findings of Lombardi et al. can easily be reproduced by this simple conventional cross-bridge model, in which the completion of one work-producing power stroke is coupled to the hydrolysis of one ATP molecule. Thus, to account for the data of Lombardi et al., there is no need to assume that cross-bridges can execute multiple power strokes per ATPase cycle, although cross-bridges may well be able to do so. The mechanism that underlies the fast regeneration of the quick tension recovery in the conventional model used here is discussed.
