Secretive proteins in E.coli, which are located in the inner membrane,the outer membrane,the periplasmic space or the environment,have a structure containing the secretion signal on the N or C terminal.These two sorts of proteins elbow through the inner membrane with the help of two series of distinguishable protein factors and realize their final position by an unelucidated mechanism. The molecule containing its signal peptide on the N terminal is assisted by protein factors of the Sec family when rushing through the cytoplasma membrane. The leading peptide might be cut off in the process. ATP and the electrical potential supply the energy for the secretion. The molecule which has secretion signal on its C terminal is helped by the Hly family members to pass the inner and outer membrave at the same time while omitting the periplasmic space.