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Lookup NU author(s): Mark Twitchett, Emeritus Prof Alfred Sykes
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This microreview describes the structure, properties and mechanisms of the purple acid phosphatases (PAP). The enzyme is isolated from mammalian, plant and bacterial sources. X-ray structural information is now available for the enzyme from pig (uteroferrin), rat and kidney beans. Features of the mechanism are the concerted action of a labile M-II centre (Fe-II or Zn-II) alongside a more inert Fe-III. The latter is effective as a conjugate-base FeOH2+, which initiates hydrolysis at the M-II-bound phosphate ester by a process involving OH- replacement of OR- at the PV. Histidine residues near to the active site help bind the phosphate and are involved in the release of OR-. Effects of replacement of the Fe-II by Mn-II, Co-II, Ni-II, Cu-II and Zn-II, and of Fe-III by Ga-III,Al-III and In-III have been studied. The mechanistic role of the (ZnZnII)-Zn-II combination in alkaline phosphatases, and other related dinuclear centres is also considered.
Author(s): Twitchett MB, Sykes AG
Publication type: Review
Publication status: Published
Journal: European Journal of Inorganic Chemistry
Year: 1999
Issue: 12
Pages: 2105-2115
Print publication date: 01/12/1999
ISSN (print): 1434-1948
ISSN (electronic): 1099-0682