Snake venom pyrophosphatase

The main component of the adenosine diphosphate sugar fraction from a Salmonella typhimurium strain was unexpectedly found to be adenosine 5 -(D-mannitol 1-pyrophosphate)190 (45). Upon treatment with acid or with snake-venom pyrophosphatase, it produces adenosine 5 -phosphate and D-mannitol 1-phosphate these observations confirm the structure assigned. 

Nucleoside Pyrophosphates. - 2.3.1 Nucleoside Diphosphate Analogues. A large variety of esters with different nucleoside and alkyl moieties (llla-j) have been synthesised in small amounts using different combinations of nucleoside triphosphate, alcohols and snake venom pyrophosphatase. Potato tube pyrophosphatase was also reported as being a possible practical biocatalyst to synthesise such nucleotide pyrophosphate-O-alkyl esters, but using more stringent reaction requirements than that of the snake venom enzyme. ... 

Chambon and coworkers also established the structure of the product as follows. Hydrolysis by snake-venom pyrophosphatase released an isomer of ADP-ribose, as shown in die scheme. This... 

Digestion of this substance XIX with a snake-venom diesterase which also contained a strong pyrophosphatase gave thymidine 5-phosphate (XX)... 

If a-casein is treated with either the crystalline pyrophosphatase of yeast at pH 7.0 (35) or with the snake venom diesterase at pH 8.2 (87), no inorganic phosphorus is released. However, if the diesterase reaction is carried out in weakly buffered solutions a small drop of pH takes place (71), indicating the exposure of acidic groups. Subsequent incubation of the diesterase-treated a-casein with prostate phosphatase at pH 6.0 hberates no more phosphorus than in the absence of the diesterase. If, how ever, prostate and intestinal phosphatase are added, 78 % of the a-casein phosphorus is set free. Since the intestinal enzyme at pH 6.0 acts on low... 

Enzymatic degradation is often useful. Pyrophosphatases have been used to produce the sugar-1-phosphate and the nucleotide. Treatment of the former with a phosphatase will give the free sugar, while the nucleotide can be broken down to the nucleoside with 5 -nucleotidase. Snake venoms have been much used, since they can contain both pyrophosphatase and 5 -nucleotidase. 

Structure of Coemyme A. The elucidation of the structure of CoA depended heavily on d radation by specific enzymes. The phosphate on carbon 3 of the adenosine was shown to be a monoester phosphate by hydrolysis with prostate phosphomonoesterase. The localization of the monoester at the 3 position was established by its sensitivity to a b nucleotidase that attacks only nucleoside 3 -pbosphates, not 2 - or 5 -phosphates. The original CoA molecule or the phosphatase product, depbospho CoA, can be split by nucleotide pyrophosphatases from potato or snake venom. These reactions permitted the identification of the adenosine phosphate portion of the molecule. The position of the phosphate on pantothenic acid cannot be determined enzymatically, but was established by studies on the synthesis of CoA from synthetic phos-phorylated pantetheines. Pantetheine is split to thiolethanolamine and pantothenic acid by an enzyme found in liver and kidney. This enzyme also attacks larger molecules, including CoA. 

It appears that most nucleotide pyrophoqihatases from mammalian tissues cleave the reduced forms of the coenzymes faster than the oxidized nucleotides. The plant nucleotide pyrophosphatases, however, q>lit DPNH, TPNH, and the oxidized coenzyme forms at equal rates. It should be pointed out, however, that an enzyme such as the potato nucleotide pyrophosphatase also attacks ATP and adenosine diphosphate (ADP), whereas the purified pigeon liver enzyme does not. The snake venom enzyme seems to split the oxidized and reduced nucleotide at equal rates. 

The enzyme NADase should not be confused with nucleotide pyrophosphatase. The products of nucleotide pyrophosphatase are nicotinamide mononucleotide and 5 -AMP. In snake venoms, there is no separate nucleotide pyrosphosphatase, but the action is due to snake venom exonuclease (phosphodiesterase). 

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