%0 Journal Article %T Understanding the dependence on the pulling speed of the unfolding pathway of proteins %A C. A. Plata %A F. Cecconi %A M. Chinappi %A A. Prados %J Physics %D 2015 %I arXiv %R 10.1088/1742-5468/2015/08/P08003 %X The dependence of the unfolding pathway of proteins on the pulling speed is investigated. This is done by introducing a simple one-dimensional chain comprising $N$ units, with different characteristic bistable free energies. These units represent either each of the modules in a modular protein or each of the intermediate "unfoldons" in a protein domain, which can be either folded or unfolded. The system is pulled by applying a force to the last unit of the chain, and the units unravel following a preferred sequence. We show that the unfolding sequence strongly depends on the pulling velocity $v_{p}$. In the simplest situation, there appears a critical pulling speed $v_{c}$: for pulling speeds $v_{p}v_{c}$ it is the pulled unit that unfolds first. By means of a perturbative expansion, we find quite an accurate expression for this critical velocity. %U http://arxiv.org/abs/1507.01376v1