In this report, we determined the distribution of trypsin in the Aqueous Surfactant Two Phases (AS2P). The influence of SDS, C12NE and AS2P on the activity and conformation of trypsin was compared. The results showed that the denaturation efficiency of SDS is much higher than that of C12NE, while the optimal mixture of SDS and C12NE, which forms AS2P, has the least effect on trypsin. In AS2P the interaction of SDS with C12NE was strong, due to the electrostatic and the hydrophobic interactions, SDS could hardly be adsorbed by the enzyme molecule. So that, trypsin in AS2P was not changed both in activity and conformation.

Key words: ULTRAVIOLET SPECTROPHOTOMETRY, SURFACTANTS, TRYPSIN, BIOACTIVE SUBSTANCE, LAURYL SODIUM SULFATE