The serine protease superfamily is a subgroup of the hydrolases

whose name comes from the conserved Se-r195 cat alyzing the substrates.Serine proteases maintain a common fold over a very long evolutionary span

in spite of divergent sequences.This class of enzymes has developed a wide variety of important biological functions.However

strongly divergent protein sequences and a mass of gene duplications make it very difficult to perform evolution analysis on the whole superfamily.In the present work

structure based evolution analysis was performed on the serine proteases superfamily using SSAP algorithm

and the structure and function evolution were analyzed

especially the effect on functions by structure evolution of the serine proteases.The research would have certain guiding significance on the relationships between protein structures and functions and the molecular design.