Identification of a tyrosine residue responsible for N-acetylimidazole-induced increase of activity of ecto-nucleoside triphosphate diphosphohydrolase 3.

ABSTRACT: Chemical modification in combination with site-directed mutagenesis was used to identify a tyrosine residue responsible for the increase in ecto-nucleoside triphosphate diphosphohydrolase 3 (NTPDase3) nucleotidase activity after acetylation with a tyrosine-selective reagent, N-acetylimidazole. The NTPDase3 ATPase activity is increased more than the ADPase activity by this reagent. Several fairly well conserved tyrosine residues (252, 255, and 262) that are located in or very near apyrase conserved region 4a (ACR4a) were mutated. These mutants were all active, but mutation of tyrosine 252 to either alanine or phenylalanine eliminated the activity increase observed after N-acetylimidazole treatment of the wild-type enzyme. This suggests that the acetylation of tyrosine 252 is responsible for

SUBMITTER: Basu S 

PROVIDER: S-EPMC2096545 | biostudies-literature | 2005 Sep

REPOSITORIES: biostudies-literature