The time required for water attack at the phosphorus atom of simple phosphodiesters and of DNA.

ABSTRACT: Phosphodiester linkages, including those that join the nucleotides of DNA, are highly resistant to spontaneous hydrolysis. The rate of water attack at the phosphorus atom of phosphodiesters is known only as an upper limit, based on the hydrolysis of the dimethyl phosphate anion. That reaction was found to proceed at least 99% by C-O cleavage, at a rate suggesting an upper limit of 10(-15) s(-1) for P-O cleavage of phosphodiester anions at 25 degrees C. To evaluate the rate enhancement produced by P-O cleaving phosphodiesterases such as staphylococcal nuclease, we decided to establish the actual value of the rate constant for P-O cleavage of a simple phosphodiester anion. In dineopentyl phosphate, C-O cleavage is sterically precluded so that hydrolysis occurs only by P-O cleavage. Measureme

SUBMITTER: Schroeder GK 

PROVIDER: S-EPMC1449644 | biostudies-literature | 2006 Mar

REPOSITORIES: biostudies-literature