Evidence for nonbridged coordination of p-nitrophenyl phosphate to the dinuclear Fe(III)-M(II) center in bovine spleen purple acid phosphatase during enzymatic turnover.

@article{Merkx1999EvidenceFN,
  title={Evidence for nonbridged coordination of p-nitrophenyl phosphate to the dinuclear Fe(III)-M(II) center in bovine spleen purple acid phosphatase during enzymatic turnover.},
  author={Maarten Merkx and Martijn W. H. Pinkse and Bruce A. Averill},
  journal={Biochemistry},
  year={1999},
  volume={38 31},
  pages={9914-25}
}
The pH dependence of the catalytic parameters k(cat) and K(M) has been determined for the Fe(III)Fe(II)- and Fe(III)Zn(II)-forms of bovine spleen purple acid phosphatase (BSPAP). The parameter k(cat) was found to be maximal at pH 6.3, and a pK(a) of 5.4-5.5 was obtained for the acidic limb of the k(cat) vs pH profile. Two different EPR spectra were detected for the phosphate complex of the mixed-valent diiron enzyme; their relative amounts depended on the pH, with an apparent pK(a) of 6. The… CONTINUE READING