Alcoholic fermentation / by Arthur Harden.

  • Arthur Harden
Date:
1932
Catalogue details

Licence: In copyright

Credit: Alcoholic fermentation / by Arthur Harden. Source: Wellcome Collection.

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    phate, and 36 per cent, as hexosephosphates (approximately 12 per cent, hexosediphosphate and 24 per cent, monophosphate). In muscle the pyrophosphate is combined with adeninenucleotide (adenylic acid), and it is probably present in yeast in some similar form. Although a pyrophosphate added to a fermenting mixture of zymin and sugar is hydrolysed to phosphate (which is then esterified), the amount present in yeast preparations does not change during a short fermentation [Boyland, 1930, 1]. The acetone precipitate from yeast- juice free from hexosephosphatase (p. 39) which was prepared by Boyland [1930, 1] readily hydrolyses pyrophosphate, so that the hydrolysis must be effected by a specific pyrophosphatase distinct from hexosephosphatase. Both in muscle and yeast, according to Meyerhof [1930, p. 173], adenylic acid pyrophosphate is probably intimately connected with the action of the co-enzyme (see p. 86), although Myrback has been unable to confirm this as regards yeast [see Euler, 1930, p. 17]. Action of Phosphatases on the Hexosephosphates. Phosphatases, capable of hydrolysing the hexosephosphoric esters, are widely distributed [Euler, 1912 ; Euler and Funke, 1912 ; Harding, 1912 ; Plimmer, 1913 ; Neuberg and Leibowitz, 1927, 2, 4, ; Robison, 1923]. The lipase of castor oil seeds, almond emulsin, the leaves of the maple, a glycerol extract of the intestinal mucous membrane of the rabbit and pig, and an aqueous extract of bran have a slow hydrolytic action on hexosediphosphate, whereas pepsin and trypsin are without effect. It is also decomposed in vitro by the kidney, spleen, and muscle of the guinea-pig [Takahashi, 1924, 1]. Feeding experiments with rabbits and dogs indicate that the diphosphate is capable of hydrolysis in the animal body, a large proportion of the phosphorus being excreted as inorganic phosphate. The ester is also decomposed and fermented by Bacillus coli communis [Manning, 1927] - It is remarkable that hexosediphosphate is not fermented or hydrolysed by living yeast, a fact observed by Euler, Harden and Young, and Ivanov, although according to the experiments of Paine [1911 ], the yeast cell is, at all events partially, permeable to the sodium salt. The enzymic hydrolysis of hexosediphosphates proceeds, like the acid hydrolysis, in stages. Hexosemonophosphate can be isolated from the products of incomplete hydrolysis of the diphosphate by yeast in presence of toluene and chloroform [Neuberg and Leibowitz, 1927, 3], both in the absence and presence of arsenate [Neuberg and Leibowitz. 1927, 5], by taka-diastase (which contains a phosphatase)
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