IMMOBILIZATION OF TUBERCIDIN AND NEBULARINE VIA 2',3'-CYCLIC ACETALS - BIOSPECIFIC AND NONSPECIFIC INTERACTION OF AFFINITY RESINS WITH ADENOSINE-DEAMINASE

Polymer-bound tubercidin (7a) and nebularine (7c) have been prepared. Condensation of tubercidin with ethyl levulinate and saponification of the product gave 2′,3′-O-[1-(2-carboxyethyl)ethylidene]tubercidin (3b). The corresponding reaction with nebularine failed, but application of the reaction sequence to 6-thioinosine gave 2′,3′-O-[1-(2-carboxyethyl)ethylidene]-6-thioinosine (4b), which was desulphurated to give 2',3'-O-[1-(2-carboxyethyl)ethylidene]nebularine (5b). The acids 3b, 4b, and 5b were coupled to 6-aminohexylagarose through their carboxyl groups, to yield the polymers 7a-c. Stronger binding of adenosine deaminase to the inhibitor gel 7c was observed than when the polymer bearing adenosine as ligand was used as an affinity resin. The non-inhibitor gel 7a showed only weak binding, which is equivalent to the non-biospecificity of polymers of type 7. © 1979.