  In cells, most of cargos are transported by motor proteins along microtubule.
Biophysically, unidirectional motion of large number of motor proteins along a
single track can be described by totally asymmetric simple exclusion process
(TASEP). From which many meaningful properties, such as the appearance of
domain wall (defined as the borderline of high density and low density of motor
protein along motion track) and boundary layers, can be obtained. However, it
is biologically obvious that a single track may be occupied by different motor
species. So previous studies based on TASEP of one particle species are not
reasonable enough to find more detailed properties of the motion of motors
along a single track. To address this problem, TASEP with two particle species
is discussed in this study. Theoretical methods to get densities of each
particle species are provided. Using these methods, phase transition related
properties of particle densities are obtained. Our analysis show that domain
wall and boundary layer of single species densities always appear
simultaneously with those of the total particle density. The height of domain
wall of total particle density is equal to the summation of those of single
species. Phase diagrams for typical model parameters are also presented. The
methods presented in this study can be generalized to analyze TASEP with more
particle species.
