The Structure and Function of the Amino Acid Specific Protease

Serine proteases have been classified into three groups on the basis of their substrate specificities: those with broad substrate specificity (subtilisin), those that recognize and cleave after positively charged residues of lysine and ariginine (trypsin), and those that cleave after negatively charged residues of glutamic and aspartic acid (V8 protease) . The first two categories are structurally well characterized, but no three-dimensional structure has been reported for protease with acidic amino acid specificity.In this study, the structure of SFase-2, a serine protease with broad substrate specificity from Streptomyces fradiae has been determined by X-ray analysis and is possible to predict the structure of SFase-1, an acidic amino acid specific protease from the same organism.