Temperature-Dependent Characteristics of an Adenylpyrophosphatase Preparation from Potatoes

Lee, Kwan-Hua; Eiler, John J.

doi:10.1126/science.114.2963.393-b

Cited by 2 publications

(3 citation statements)

References 6 publications

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“…The potato-apyrase solution used was prepared as described by Lee and Eiler (1951). The preparation was neutralized with Tris base and stored frozen until use.…”

Section: Methodsmentioning

confidence: 99%

Some Tests of the Hypothesis that the Sodium-Ion Gradient Furnishes the Energy for Glycine-active Transport by Pigeon Red Cells^*

Vidaver¹

1964

Biochemistry

106

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Three further tests of the Na +-gradient hypothesis are applied. These, like one used earlier, support the hypothesis, which is therefore considered to be established. The findings with the three new tests are as follows. (1) Two Na ions enter the cells in concert with one glycine, as expected from the previously reported kinetic dependence of glycine entry on (Na4)2. (2) A system with high but equal concentrations of Na+ inside and out, which does not pump glycine due to the absence of a Na+ gradient, can be caused to pump glycine (out) by a Donnan effect. In the presence of the Donnan electrical potential there is a Na +-electrochemical gradient even though there is no Na+-concentration gradient. (3) No correlation is found between the con-* The work described in this paper was supported by research grants to Professor F. Haurowitz from the National Science Foundation (NSF G16345

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“…The potato-apyrase solution used was prepared as described by Lee and Eiler (1951). The preparation was neutralized with Tris base and stored frozen until use.…”

Section: Methodsmentioning

confidence: 99%

Some Tests of the Hypothesis that the Sodium-Ion Gradient Furnishes the Energy for Glycine-active Transport by Pigeon Red Cells^*

Vidaver¹

1964

Biochemistry

106

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“…It has been reported that above 7°C. potato apyrase preparations split off two inorganic phosphate groups from adenosine triphosphate, whereas below 7°o nly one phosphate group was split off (57). It may not be too far-fetched to relate this observation to a similar critical temperature for the well-known starch-sucrose shift in potatoes.…”

Section: Enzymes That Hydrolyze Phosphate Estersmentioning

confidence: 87%

“…The possibility that the second phosphate is split off owing to the presence of myokinase (or, more correctly, adenylatekinase) (ATP + AMP = 2ADP) was tested and no evidence for the presence of myokinase in potatoes could be found (52). Although the apyrase of muscle tissue is specifically activated by calcium ions, potato apyrase preparations have been reported as being activated (54,57) and not activated (99) by calcium salts. These and other discrepancies [such as the relative values of the rate constants of the two hydrolyzable phosphate linkages of adenosine triphosphate (57)] raise the question as to the enzymic homogeneity and identity of different apyrase preparations as prepared by different investigators.…”

Section: Enzymes That Hydrolyze Phosphate Estersmentioning

confidence: 99%

Enzymes, Enzyme Systems of the White Potato

Schwimmer¹

1953

J. Agric. Food Chem.

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Survey of the literature on enzymes of white potatoes discloses that this tuber and its constituent enzymes are useful in the field of enzyme chemistry as a source material for large scale preparative purposes, for the elucidation of the mechanisms of starch transformation in plants, and as an analytical tool contributing to knowledge of the phosphate linkages in coenzymes and proteins. Positive evidence exists for the presence of enzymes involved in (and for the operation of) the biologically ubiquitous glycolytic, tricarboxylic, and cytochrome terminal oxidative systems in this tuber. Studies of the relationship of these systems and other enzymes to the problems of enzymatic browning of raw potatoes via phenol oxidase on the one hand, and to the nonenzymatic browning of processed products due to accumulation of reducing sugars on the other, are still in a formative but promising stage. Only meager knowledge is available concerning the enzymic mechanisms involved in the transformation of sucrose and nitrogenous constituents of the potato. THE CHEMICAL COMPOSITION OF THE white potato tuber (Solarium tuberosum L.) and changes in its composition as related to variety, culture, harvest, storage, and industrial processing have received detailed attention in numerous studies (24, 80). Yet the level of accumulation of any particular substance in the potato, as in any living organism, can in principle be traced back to the resultant action of the enzymes and enzyme systems catalyzing its synthesis and decomposition. Very few

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Temperature-Dependent Characteristics of an Adenylpyrophosphatase Preparation from Potatoes

Cited by 2 publications

References 6 publications

Some Tests of the Hypothesis that the Sodium-Ion Gradient Furnishes the Energy for Glycine-active Transport by Pigeon Red Cells^*

Some Tests of the Hypothesis that the Sodium-Ion Gradient Furnishes the Energy for Glycine-active Transport by Pigeon Red Cells^*

Enzymes, Enzyme Systems of the White Potato

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Temperature-Dependent Characteristics of an Adenylpyrophosphatase Preparation from Potatoes

Cited by 2 publications

References 6 publications

Some Tests of the Hypothesis that the Sodium-Ion Gradient Furnishes the Energy for Glycine-active Transport by Pigeon Red Cells*

Some Tests of the Hypothesis that the Sodium-Ion Gradient Furnishes the Energy for Glycine-active Transport by Pigeon Red Cells*

Enzymes, Enzyme Systems of the White Potato

Contact Info

Product

Resources

About

Some Tests of the Hypothesis that the Sodium-Ion Gradient Furnishes the Energy for Glycine-active Transport by Pigeon Red Cells^*

Some Tests of the Hypothesis that the Sodium-Ion Gradient Furnishes the Energy for Glycine-active Transport by Pigeon Red Cells^*