Hydrolase phosphoric diester

A Nucleotidases Phosphoryltransfer from a nucleotide to water as an acceptor molecule. (Nucleotides are cleaved hydrolytically). 3.1.3. (3.1.4. Phosphoric ester hydrolases Phosphoric diester hydrolases)... 

Phosphatases of documented or potential interest in the context of this book include phosphoric monoester hydrolases (EC 3.1.3), phosphoric diester hydrolases (EC 3.1.4), and phosphoric triester hydrolases (EC 3.1.8). 

Phosphatases are numerous and important enzymes (see also Chapt. 2). They are classified as phosphoric monoester hydrolases (phosphatases, EC 3.1.3), phosphoric diester hydrolases (phosphodiesterases, EC 3.1.4), triphosphoric monoester hydrolases (EC 3.1.5), diphosphoric monoester hydrolases (pyrophosphatases, EC 3.1.7), and phosphoric triester hydrolases (EC 3.1.8) [21] [63]. Most of these enzymes have a narrow substrate specificity restricted to endogenous compounds. However, some of these enzymes are active toward xenobiotic organophosphorus compounds, e.g., alkaline phosphatase (EC 3.1.3.1), acid phosphatase (EC 3.1.3.2), aryldialkylphosphatase (para-oxonase (PON1), EC 3.1.8.1) and diisopropyl-fluorophosphatase (tabunase, somanase, EC 3.1.8.2) [64 - 70]. However, such a classification is far from definitive and will evolve with further biochemical findings. Thus, a good correlation has been found in human blood samples between somanase and sarinase activities on the one hand, and paraoxonase (PON1) type Q isozyme concentrations on the other [71]. 

In a classification from 1992 (International Union of Biochemistry, 1992) hydrolases of OP were described as a special entity as phosphoric triester hydrolases which comprise three groups of enzymes phosphoric monoester hydrolases (EC 3.1.3), phosphoric diester hydrolases (EC 3.1.4), and phosphoric triester hydrolases (phosphotriesterases) (EC 3.1.8). Phosphoric triester hydrolases are further divided in two similar subgroups aryldialkylphos-phatases (EC 3.1.8.1) and diisopropylfluorophosphatases (EC 3.1.8.2). 

NUCLEOTIDASES AND RELATED ENZYMES - PHOSPHORIC DIESTER HYDROLASES... 

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