R. Kaminski et al., MONOSELENOPHOSPHATE - ITS HYDROLYSIS AND ITS ABILITY TO PHOSPHORYLATEALCOHOLS AND AMINES, Bioorganic chemistry, 25(4), 1997, pp. 247-259
The rate of hydrolysis of monoselenophosphate, the labile selenium don
or compound required for the synthesis of selenium-dependent enzymes a
nd seleno-tRNAs, was determined by P-31 NMR spectroscopy. The rate dep
ended on the pH of the solution and was maximal at a pH similar to 7.
This suggests that the dianion is the species that reacts fastest. Add
ed alcohols and amines do not significantly affect the rate of hydroly
sis but are phosphorylated. The entropy of activation is positive for
the hydrolysis of monoselenophosphate. These data suggest a dissociati
ve in nature mechanism for the hydrolysis of monoselenophosphate invol
ving a monomeric metaphosphate-like transition state in the rate-deter
mining step. (C) 1997 Academic Press.