Phosphatases: general

Although values for the Zn(II) content of alkaline phosphatase generally range from 2 to 4 [Applebury and Coleman (48) have found values as high as 7, and the tetramer is believed to contain 16 (46)], there is general agreement that only two Zn(II) are necessary for activity of the enzyme (27, 36, 50-54)-... 

Kinetics and inhibition of rat and avian alkahne phosphatases. General... 

Phosphorothioates generally protect normal tissues more than tumors. Tumor protection reported in some animal studies can pardy be explained by physiological effects of the particular dmgs, which are specific to rodents (4). WR-2721 does not appear to protect human and most animal tumors, apparentiy because of the low availabiUty of the dmg to tumor cells (4). Many tumors appear to have a reduced capillary density (44), which may mean that these tumors have altered levels of alkaline phosphatase, the enzyme that converts WR-2721 to WR-1065. A reduced abiUty of thiols to protect the hypoxic cells characteristic of many tumors may also contribute to their selectivity for normal tissues. The observation that WR-1065 protects cultured normal human fibroblasts, but not fibrosarcoma tumor cells, suggests that additional factors may contribute to the selectivity of radioprotection by WR-2721 m vivo (18). 

Many more papers deal with rhizosphere phosphatase activity (63-83) in the presence of a number of different plant species this will partly be due to the simplicity of the enzyme activity assay (85,86) and the generally reported, well-correlated variation trends among organic and inorganic phosphorus content and phosphatase activity. More precisely, closer to the roots, the inorganic P depletion zone in comparison with bulk soil is more pronounced in addition, organic and inorganic P contents are inversely correlated, and the mineralization rate of or-... 

Enzymes that react with a specific type of ester linkage are known as general hydrolysing enzymes. Thus lipases hydrolyse a wide range of organic esters. Generally, phosphatases will break down phosphate esters into phosphoric acid and an alcohol. 

Van der Loos CM, Teeling P. A generally applicable sequential alkaline phosphatase immunohistochemical double staining. I. Histotechnol. 2008 31 119-127. 

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