scholarly journals Studies on enzyme action. IV.—The sucroclastic action of acids as contrasted with that of enzymes.

1904 ◽  
Vol 73 (488-496) ◽  
pp. 526-537 ◽  
Author(s):  
Edward Frankland Armstrong ◽  
Robert John Caldwell ◽  
Henry Edward Armstrong
Keyword(s):  
Cane Sugar ◽  
Enzyme Action ◽  
Milk Sugar ◽  
New Instrument ◽  
Hydrolysis Of

Not only are the various bioses hydrolysed at very different rates by enzymes but they are also known to differ in their behaviour towards acids: cane sugar being hydrolysed with the greatest facility, whilst maltose is acted upon but slowly. The experiments described in this communication were instituted primarily with the object of ascertaining the behaviour of milk sugar, of which nothing was known. The hydrolysis of cane sugar under the influence of acid was carefully investigated by Wilhelmy as far back as 1850, with the aid of the polariscope, then a new instrument.

scholarly journals Studies on enzyme action. XI.-Hydrolysis of raffinose by acids and enzymes

1908 ◽  
Vol 80 (540) ◽  
pp. 312-321 ◽  
Keyword(s):  
Cane Sugar ◽  
Point Of View ◽  
Enzyme Action ◽  
Milk Sugar ◽  
Previous Communication ◽  
Specific Behaviour ◽  
Hydrolysis Of

In a previous communication of this series (vol. 74, p. 191), it is pointed out that the various glucosides are hydrolysed by acids at very different rates, the relative values being approximately of the order shown in the following table:- α -Methylglucoside....100 β -Methylglucoside....180 α -Methylglucoside....540 β -Methylglucoside....880 Salicin ( a β -glucoside)....600 Milk-sugar ( α β -galactoside)....720 Maltose (an α -glucoside)....740 Cane-sugar, it is to be remembered, is hydrolysed at a rate vastly more rapid-at least 1000 times as rapidly as maltose, in fact. These differences, taking into account the peculiar specific behaviour of enzymes as hydrolytic agents, raise questions of interest from the chemical side and they are of no slight significance perhaps also from a biological point of view.

Synthesis of Milk-Sugar and Cane-Sugar

1880 ◽  
Vol 9 (219supp) ◽  
pp. 3491-3491
Author(s):  
E. Demole
Keyword(s):  
Cane Sugar ◽  
Milk Sugar

scholarly journals Studies on enzyme action. V.—Hydrolysis of isomeric glucosides and galactosides by acids and enzymes.

1905 ◽  
Vol 74 (497-506) ◽  
pp. 188-194 ◽  
Author(s):  
Edward Frankland Armstrong ◽  
Henry Edward Armstrong
Keyword(s):  
Relative Stability ◽  
Intrinsic Properties ◽  
Enzyme Action ◽  
Test Materials ◽  
Hydrolysis Of ◽  
Made In

In view of the use constantly made, in contrasting the action of sucroclastic enzymes, of the stereoisomeric α- and β-methyl glucosides and the corresponding galactosides as test materials, it was desirable to gain some idea of the relative stability of these four compounds in presence of acids and wherever possible towards enzymes, a know­ledge of their behaviour being of importance, both as throwing light on their intrinsic properties and for the purpose of correlating the activities of the various compounds amenable to hydrolysis.

Studies on enzyme action. VI.—The sucroclastic action of acids as contrasted with that of enzymes. Part II.

1905 ◽  
Vol 74 (497-506) ◽  
pp. 195-201 ◽  
Author(s):  
Edward Frankland Armstrong ◽  
Robert John Caldwell ◽  
Henry Edward Armstrong
Keyword(s):  
Linear Function ◽  
Cane Sugar ◽  
Enzyme Action ◽  
Logarithmic Law

In accordance with the theory put forward in our former paper, it was to be expected that on hydrolysing cane sugar with sufficiently dilute acids the course of the change would not follow the simple logarithmic law but that it would approximate, during the earlier period, to a linear function of the time. This supposition has been confirmed by experiments made very carefully to test this point.

scholarly journals The Hydrolysis of Maltose by Hydrochloric Acid under the Herzfeld Conditions of Inversion

1914 ◽  
Vol 6 (4) ◽  
pp. 413-416 ◽  
Author(s):  
A. J. Kluyver ◽  
William A. Davis
Keyword(s):  
Citric Acid ◽  
Hydrochloric Acid ◽  
Plant Extracts ◽  
Cane Sugar ◽  
Hydrolysis Of

It is shown that contrary to the statements of Kluyver and others, maltose undergoes slight hydrolysis (to the extent of about 2% when 1% solutions of maltose are used) when heated with hydrochloric acid under Herzfeld conditions. It is preferable therefore to adopt 10% citric acid, under the conditions formerly laid down, in estimating cane sugar in plant extracts when maltose is likely to be present.

scholarly journals Studies of the processes operative in solutions. XXIII.—The hydrolysis of methylic acetate by acids

1912 ◽  
Vol 87 (599) ◽  
pp. 582-603
Keyword(s):  
Simple Formula ◽  
Free Water ◽  
Acid Catalyst ◽  
Cane Sugar ◽  
Rate Of Change ◽  
Active Factor ◽  
Primary Object ◽  
Rate Of Hydrolysis ◽  
Extreme Care ◽  
Hydrolysis Of

One of the main objects in view throughout this series of studies of the processes operative in solutions has been to discover the nature of the changes which attend dissolution, particularly the extent to which substances undergo hydration when dissolved in water; another primary object has been to unravel the nature of the process of hydrolysis. The evidence thus far obtained has been always such as to show that the phenomena are far more complex than is usually supposed and even to discredit the interpretation that it is now customary to give of them. In Communication XII of the series, I have given an account of experiments made with improved apparatus and with extreme care of the behaviour of cane sugar towards chlorhydric and nitric acids and of the influence of certain chlorides and nitrates on the rate of change. It was shown that the rate of hydrolysis could not be accurately expressed by any simple formula, as it was not even proportional to the concentration of the sugar, though it was approximately so when the molecular ratio of sugar to water was not high. Evidence was adduced to show that water as such, i.e. free water, did not play any part in the change but acted solely as solvent and that the active factor of the interaction besides the sugar was the hydrated acid catalyst.

scholarly journals Studies on enzyme action. XII.-The enzymes of emulsin

1908 ◽  
Vol 80 (540) ◽  
pp. 321-331 ◽  
Keyword(s):  
Aspergillus Niger ◽  
Small Proportion ◽  
Enzyme Action ◽  
Milk Sugar ◽  
The Subject ◽  
Made In

Emulsin has frequently been the subject of discussion in this series of studies: thus the rate at which it hydrolyses milk-sugar was considered in No. II (Vol. 73, pp. 507, 515) and its action contrasted with that of Kephirlactase, which was shown to act more rapidly than emulsin. In No. III (vol. 73, p. 518) it was pointed out that whilst Kephir-lactase is controlled by galactose and scarcely at all by galactose. These conclusions were confirmed by experiment with the methyl-glucosides and galactosides (p.523). In No. V (Vol. 74, p. 188) the question was discussed whether emulsin proper hydrolyses milk-sugar or whether, as Bourquelot and Hérissey have contended, emulsin contains a small proportion of lactase: against this assumption it was argued that the curve was not of the form to be expected if only a small quantity of lactase were present; that whereas Kephir-lactase was controlled by galactose alone, emulsin was most retarded by glucose and only to a slight extent by galactose, also that the curves for emulsin differed in character from those for lactase. Attention was directed, however, to Pottevin’s statement that Aspergillus niger contains an enzyme capable of hydrolysing β -glucosides, but not β -galactosides nor milk-sugar. In No.X (B, vol. 79, p. 360) some of the statements made in earlier studies were rectified and it was announced that evidence had been obtained, to the presence of a distinct enzyme capable of hydrolysing only β -glucosides. While admitting this to be the case, however, we may point out that the conclusions we have to bring forward involve merely a different reading of the facts: the facts have been correctly advanced on both sides.

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