A Study of the Polyphenol Oxidase System in Potato Tubers

Boswell, J. G.; Whiting, G. C.

doi:10.1093/oxfordjournals.aob.a084039

Cited by 57 publications

(14 citation statements)

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“…6) which depressed the respiration, carbohydrate metabolism, and water absorption, also retarded protein synthesis,7 whereas the stronger potassium salt, 8 7 The differences between treatments 1 and 6 are not large, but they are confirmed by a large amount of evidence which will be presented in a subsequent paper. 8 The small differences between treatments 1 and 2 cannot be regarded as real since they have not been confirmed in the extensive experiments to be discussed later. 9 These effects of cations should be clearly distinguished from the effects of acute mineral deficiency.…”

Section: Effects Of Salts and Oxygen At 23°c On Starch And Sugar Conmentioning

confidence: 73%

The Balance Sheet of Metabolites For Potato Discs Showing the Effect of Salts and Dissolved Oxygen on Metabolism At 23° C1

Steward¹,

Stout²,

Preston³

1940

Plant Physiology

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IntroductionThis paper presents a summarv of the effects of various salt and oxi-gen treatments so chosen that they comprise a range of conditions of peculiar interest to the student of salt accumulation.In any account of plant metabolism important processes may evade recognition unless a balance sheet of the principal metabolites can be prepared. Such balance sheets have rarely been attempted although the work of RAISTRICK et al. (31) on fungi is a notable exception. The work of RAISTRICK was concerned, however, with the use of organisms under standardized nutritional conditions to effect organic synthesis and transformations; it did not describe the effect on the metabolism of a given organism of a range of external and nutritional conditions. There is nieed of more attention to balance sheets of plant metabolism and especially so with reference to the vexed problems of respiration. Deviations from the familiar equations C6H1206 + 602 = 6CO2 + 6H20 + 674,000 cal. and C6H1206 = 2C2H50H + 2CO2 + 25,000 cal. often tacitly accepted as representative of plant respiration, are multiplying. The work of GANE and others (11,16,17) has demonstrated the production of volatile substances other than carbon dioxide and large discrepancies between respiration and the simple equations above may be encountered. For example, ARCHBOLD and BARTER (1) observed that the loss of sugar and acid in respiring apples exceeded by 17 to 30 per cent. the carbon dioxide evolved. On the other hand, DASTUR and DESAI (10) founid that in the respiration of rice the carbon dioxide evolved exceeded the utilization of sugar and they believe that acids formed durino the synthesis of protein form the source of the carbon involved. Again Luidegardh (23) states that in excised wheat roots 30 to 60 per cent. more glucose disappears than is accounted for by respiration and he tacitly assumes that the discrepalne is a measure of the sugar used in growth. In experiments with excised roots HOAGLAND has observed cases in which a very rapid disappearance of sugar occurred anid carbon dioxide productioni conitinued after the cells seemed to be free of sugar.2 1 This is the second of a series of papers on The Biochemistry of Salt Absorption by Plants. The authors are inidebted to PROF. HOAGLAND for proof-reading this paper.2 Results privately comlmunicated. PLANT PHYSIOLOGY From our present standpoint the outstanding fault in the above equations is lack of any implication that respiration concerns substances other than carbohydrates or that aerobic respiration and nitrogen metabolism are mutually dependent processes in plants.The variation between replicate samples of standard potato discs is small (47) and the effect of metabolism on the constituents of the tissue can be obtained by difference between the composition of the initial and final, experimentally treated, batches of discs. It is possible, therefore, to draw up a balance sheet with reference to any metabolite, e.g., carbohydrate, the fate of which is known with sufficient certainty so that its pr...

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Section: Effects Of Salts and Oxygen At 23°c On Starch And Sugar Conmentioning

confidence: 73%

The Balance Sheet of Metabolites For Potato Discs Showing the Effect of Salts and Dissolved Oxygen on Metabolism At 23° C1

Steward¹,

Stout²,

Preston³

1940

Plant Physiology

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“…In recent years there has been active interest in polyphenoloxidase as the terminal oxidase in the respiration of the potato tuber (3,5,6) and spinach leaves (4,27). In Chlorella cells copper "poisons" have been found to inhibit both photosynthesis and respiration (9).…”

Section: Discussionmentioning

confidence: 99%

“…WARBURG and LPTTGENS (26), working with similar preparatioins from spinach and sugar beets, attributed about a quarter of the polyphenoloxidase activity of the crude green PIG. 6. Polyphenoloxidase activity of cytoplasmic fluids with and without the addition of a crude polyphenoloxidase preparation from potatoes.…”

Section: Is the Localization Of Polyphenoloxidase Activity In The Chlmentioning

confidence: 99%

COPPER ENZYMES IN ISOLATED CHLOROPLASTS. POLYPHENOLOXIDASE IN BETA VULGARIS

1949

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“…Evidence has been presented that tyrosinase may act as a terminal oxidase in plant respiration, the quinone acting as a hydrogen acceptor (e.g. Boswell & Whiting, 1938;Baker & Nelson, 1943). In this connexion Robinson & Nelson (1944) point out that if insufficient hydrogen donors are present the quinones give rise to inactive melanin products.…”

Section: Experimental and Resultsmentioning

confidence: 99%