title: Kinetic characteristics and binding process of substrate analogs to the adenosine deaminase in the marine mussel, Mytilus edulis.
abstract: 1. The purified mussel enzyme deaminated several adenosine analogs with different Km and relative Vmax values. Affinity for adenine was similar to that for adenosine but the deamination rate was extremely slow. 2. Purine riboside was competitive, coformycin was a tight, slow binding inhibitor, and inhibition by both these compounds was pH-dependent. 3. Inosine, hypoxanthine, guanosine and 6-mercapto-purine riboside were slightly inhibitory. 4. The results suggested that initial binding of the substrate was guided by the adenine moiety followed by a stereospecific steering due to a ribose-dependent distortion in the complex to facilitate nucleophilic attack at C-6.
authors: Department of Biology, Faculty of Science, Niigata University, Japan.
authors: T
authors: T
authors: Ogawa
authors: Y
authors: Y
authors: Aikawa
authors: T
authors: T
authors: Aikawa
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives; D000243:Adenosine Deaminase / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D049872:Bivalvia / Q000201:enzymology*; D002417:Cattle; D004064:Digestive System / Q000201:enzymology; D007422:Intestines / Q000201:enzymology; D007700:Kinetics; D009700:Nucleoside Deaminases / Q000378:metabolism*; D013045:Species Specificity; D013379:Substrate Specificity
chemical_list: D009700:Nucleoside Deaminases; D000243:Adenosine Deaminase; D000241:Adenosine