[The role of tryptophan in appearance of adenosine deaminase activity].

Chemical modification of tryptophan residues with N-bromosuccinimide and their photooxidation in the presence of trichloroethanol inhibited the activity of adenosine deaminase purified from gray and white matter of calf brain. Only two of six modified residues are important for enzyme activity. Preliminary kinetic data indicate that these essential tryptophan residues are adjacent to the substrate-binding site of the enzyme.