Major enhancement of the affinity of an enzyme for a transition-state analog by a single hydroxyl group.
The compound 1,6-dihydropurine ribonucleoside, prepared by reduction of nebularine in the presence of ultraviolet light, is bound by adenosine deaminase approximately 10(8)-fold less tightly than 6-hydroxy-1,6-dihydropurine ribonucleoside, a nearly ideal transition-state analog. This difference in affinities, which is associated with the presence of a single hydroxyl group in the second compound, suggests the degree to which one or a few hydrogen bonds may stabilize the transition state in an enzyme reaction of this type.
Kati
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WM
Department of Biochemistry, University of North Carolina, Chapel Hill 27514.
Wolfenden
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D000243:Adenosine Deaminase / Q000378:metabolism*; D058892:Adenosine Deaminase Inhibitors; D006860:Hydrogen Bonding; D006878:Hydroxides; D008024:Ligands; D009700:Nucleoside Deaminases / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013816:Thermodynamics
D058892:Adenosine Deaminase Inhibitors; D006878:Hydroxides; D008024:Ligands; D009700:Nucleoside Deaminases; D000243:Adenosine Deaminase