Binding specificities of adenosine aminohydrolase from calf intestinal mucosa with dialdehydes derived from hexofuranosyladenine nucleosides.

A series of nucleoside dialdehydes has been prepared as powders after treatment of hexofuranosyladenine nucleosides with paraperiodic acid; thus, periodate oxidation and purification of the products yielded dialdehydes derived from 9-(6-deoxy-beta-D-gulofuranosyl)adenine (1), 9-(6-deoxy-beta-L-gulofuranosyl)adenine (2), 9-(alpha-D-rhamnofuranosyl)adenine (3), 9-(alpha-L-rhamnofuranosyl)adenine (4), 9-(6-deoxy-alpha-L-talofuranosyl)adenine (5), 9-(5,6-dideoxy-beta-L-ribo-hex-5-enofuranosyl)adenine (6), and 9-(5,6-dideoxy-beta-D-ribo-hex-5-enofuranosyl)adenine (7). Nucleoside dialdehydes 1, 4, and 5 were weak substrates for adenosine aminohydrolase from calf intestinal mucosa. Dialdehydes 6 and 7 were not substrates for the enzyme but were rather strong competitive inhibitors, with Ki values of 50 and 7 microM, respectively. Dialdehydes 2 and 3 did not bind to the enzyme at all. The dialdehydes did not exhibit time-dependent inhibition, suggesting that they did not form covalent bonds with the protein.