Alkaline phosphodiesterase

In another approach subcellular fractionation of human PMNs, stimulated in vitro with phorbol myristate acetate or opsonized zymsan, was performed by rate-zonal centrifugation in sucrose gradients By varying the centrifugal force the NADPH oxidase could be separated from the activities of enzymes in the lysosomal granules but was similar to the distribution of markers for the plasma membrane, aryl phosphatase, alkaline phosphodiesterase I, and acid aryl phosphatase. 

Alkaline phosphodiesterase 1 (EC 3.1.4.1) hydrolyses polyribonucleotides or oligodeoxyribonucleo-tides which have a free 3 -OH group, sequentiaUy U-berating 5 -nucleoside monophosphate (Khorana 1961). This enzyme has been recognised as a component of the plasma membrane of rabbit alveolar... 

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]. 

SVPDE/AP snake venom phosphodiesterase and alkaline phosphatase t-BOC tm-butoxycarbonyl (group)... 

Alkaline phosphatase, acid phosphatase, 5 -nucleotidase, monoacyl hydrolase, ribonuclease, type 1 phosphodiesterase, adenosine triphosphatase, adenyl cyclase, glycosyl transferase, esterases and disaccharidase have been biochemically or cytochemically demonstrated in the tegument of various cestodes (152, 210, 250, 374, 491, 620, 624-626, 651, 718, 763, 776, 898). Several of these enzymes - phosphatases, 5 -nucleotidase and phosphodiesterase - probably have a digestive and/or absorptive function but the role of the others is uncertain. 

Alkaline phosphatase and phosphodiesterase activities of the brush border membrane of four strains of the tapeworm Hymenolepis diminuta. Journal of Parasitology, 72 809-11. 

At neutral and slightly alkaline pH, N-chlorosuccinimide (NCS) and N-chloro-p-toluenesulfonamide (chloramine-T) oxidize methionine residues in peptides and proteins to methionine sulfoxides (31). Chlor-amine-T is more selective than NCS it does not react with tryptophan whereas NCS does. However both of these reagents react with cysteine. Treating the Ca2+-dependent protein modulator with NCS in the presence of Ca2+ resulted in selective oxidation of methionines 71, 72, 76, and possibly 109 in the modulator sequence with concomitant loss in interaction with cyclic nucleotide phosphodiesterase (32). Methionine residues have been implicated in the activation of cyclic nucleotide phosphodiesterase by the Ca2+-dependent protein modulator. 

Tritylagarose (29) binds enzymes in a reversible fashion through hydrophobic forces, providing another kind of reversible immobilization. Several enzymes, such as alkaline phosphatase, fl-galactosidase, lactate dehydrogenase, and spleen phosphodiesterase, have been immobilized (29). 

The base composition of a nucleic acid can be determined quite simply by digesting the DNA or RNA with non-spedfic phosphodiesterases and analysing the nudeotide or nucleoside products combined treatment with Serratia marcescens nuclease (i.e., Benzonase ) and PI nuclease yields nudeoside-5 -monophosphates. Further treatment with alkaline phosphatase leads to dephosphorylation and the formation of nucleosides that can be analysed by RP-HPLC. This procedure can also be used to detect and quantitate modified nucleotides and nucleosides. The base composition of double stranded nucleic acids follows the well known Chargaff rules ... 

Acid or alkaline hydrolysis preferentially breaks the 5 -bond, which is in contrast to the action of phosphodiesterase which attacks only the 3 -bond. 

The syntheses of dithymidylyl-3, 5 -phosphorofluoridate and phosphorothiof-luoridate (87) and (88) have been described. These involved the fluorinolysis of the P-Se bond in the bis-dimethoxytrityl selenomethyl esters (89) and (90). Compounds (87) and (88) were reported to be hydrolytically unstable, with no inhibitory activity on the snake venom and spleen phosphodiesterases and alkaline phosphatases. Finally, neither was considered as a highly toxic dinuc-leotide. ... 

Phosphodiesterase activity of alkaline phosphatase in ATP-initiated Ca and phosphate deposition in isolated chicken matrix vesicles. J Biol Chem 280 37289-37296... 

Zalatan JG, Perm TD, Brunger AT et al (2006) Structural and functional comparisons of nucleotide pyrophosphatase/phosphodiesterase and alkaline phosphatase implications for mechanism and evolution. Biochemistry 45 9788-9803... 

A second synthesis of the same compound starts with (297), available from (266) by the action of alkaline phosphatase followed by acidolysis. With ammonia and cyclohexyl isocyanide, the product from (297) is (298 R =Et, R =NHC H cyclo). Phosphodiesterase I removes the ester group from this, and further treatment with a-chymotrypstn yields, as before, the... 

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