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.

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. XXII.--Lipase (IV)-The correlation of synthetic and hydrolytic activity

1914 ◽  
Vol 88 (601) ◽  
pp. 176-189 ◽  
Keyword(s):  
Thin Film ◽  
Aqueous Solution ◽  
Fatty Acids ◽  
Comparative Study ◽  
Hydrolytic Activity ◽  
Mass Action ◽  
Enzyme Action ◽  
Previous Communication ◽  
Hydrolysis Of ◽  
Higher Fatty Acids

In the previous communication on this subject, in which the behaviour of Lipase towards ethereal salts generally was discussed, it has been argued that the enzyme is specially fitted to determine the hydrolysis of the insoluble, oily, glyceric salts of the higher fatty acids but is not suited to act in aqueous solution : we expressed the opinion that interaction must be supposed to take place at between surfaces separated only by a thin film of water at most-in other words, that water in excess is inimical to the occurrence of change. The results we advanced, in conjunction with those deduced from the study of other enzymes, notably urease, also led us to conclude that it is impossible to apply the laws of mass action directly to the interpretation of the causes effected by Lipase. Previously we have directed our attention only to the hydrolytic activity of the enzyme : numerous observation are on record which prove that, whether of animal or vegetable origin, it can act reversibly but no comparative study of the two processes has been made hitherto in the case of facts.

scholarly journals Studies on enzyme action. XIII.—Enzymes of the type

1910 ◽  
Vol 82 (556) ◽  
pp. 349-367 ◽  
Keyword(s):  
Hydrogen Cyanide ◽  
Specific Enzyme ◽  
Enzyme Action ◽  
Milk Sugar ◽  
Previous Communication

In the previous communication of this series (No. XII, 1908, B, Vol. 80, pp. 321—329) the contention was advanced that “emulsin’’prepared from sweet almonds contains at least three distinct enzymes, viz., amygdalase , a β-glucase and gluco-lactase : the first of these, amygdalase, being the enzyme by which amygdalin is resolved into glucose and Fisclier’s glucoside, β -glucase that by which β -glucosides are hydrolysed, gluco-lactase that which hydrolyses milk sugar. Meanwhile the striking discovery has been made by Rosenthaler that emulsin has the property of inducing the formation of dextro-rotatory benzylidenecyanhydrol—such as may be obtained from amygdalin—from benzaldehyde and hydrogen cyanide; this raises the question whether there may not also be present in “emulsin” a specific enzyme capable of operating on the cyanophoric radicle of amygdalin and of resolving it into hydrogen cyanide and benzaldehyde. To avoid periphrasis this hypothetical enzyme may be spoken of as benzcyancise.

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 The theory of photographic processes, part II: On the chemical dynamics of development, including the microscopy of the image

1905 ◽  
Vol 76 (509) ◽  
pp. 217-234 ◽  
Keyword(s):  
Heterogeneous Systems ◽  
Point Of View ◽  
The Other ◽  
Chemical Dynamics ◽  
Practical Point ◽  
Previous Communication ◽  
The One

The investigation of development described in a previous communication was extended by the application of microscopic methods. The fact that both the silver haloid and the resulting silver are distributed through the film in the form of particles of minute but measurable size, allows us in this way to detect finer qualitative differences in, and to draw independent deductions on the processes of exposure and development. The size of the grain is important, both from the practical point of view and from the theoretical: in the one case as bearing on spectroscopical and astronomical photography, in the other on account of the great importance of the degree of surface-extension for heterogeneous systems. The method has been used previously by Abney, Abegg, Kaiserling, Ebert, and others, but by far the most systematic and important inquiry is that of K. Schaum and V. Bellach.

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.

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