Technical Inform ation

Nucleoside 5'-triphosphate derivatives and their analogs (NTPDA) have been extremely helpful in explaining many important details of the mechanism of reactions catalyzed by a family of NTP dependent enzymes. Different versions of NTPDAs represent various modifications of the bases, sugars, triphosphate chain and the combinations of those. Many of the modifications result in changes in the essential properties of the nucleoside 5'-triphosphates, and most importantly their behavior in the enzymatic reactions. 1. Substrate activity of NTPDAs often changes compared to that of the parent NTPs (usually reduced). 2. NTPDAs may become inhibitors of the enzymatic reactions through various mechanisms. For example: a. NTPDAs (depending on the type of modification) may physically block the binding, catalytic or allosteric sites of the enzyme thus competing with the substrate, the reaction product or an allosteric regulator(s). b. NTPDAs may cause a termination of the enzymatic chain reaction by producing a modified product lack-ing the chemical function required for continuation of the enzymatic process. c. NTPDAs possessing a reactive group(s) may also cause a chemical modification of the crucial enzyme functions responsible for substrate recognition, catalytic action, or conformation stability of the peptide structure (or disrupt the association forces keeping the functional multiunit enzymes)