ASA SECTIONAL TRANSACTIONS.—B. 
Monday, September 17. 
11. Dr. E. F. Armsrrone, F.R.S.—Enzymes. 
Enzymes are to be regarded as colloid catalysts. It is customary to think 
of them as definite chemical entities, but the activity associated with them is 
connected with certain aggregates of groups in a very much larger molecule. 
Probably the enzyme, as such, is incapable of existing, and the larger molecule 
may well -be variable in its nature. Their activity in the main is hydrolytic— 
that is, they activate water molecules, and in special cases they also bring 
about synthetic action; there is also the class of oxidising and reducing enzymes 
which act again in activating water so as to give oxygen to one and hydrogen 
to another acceptor. The study of enzymes is thus intimately bound up with 
that of the behaviour of water in solutions. 
Enzymes are obtained from animal and vegetable tissues in a concentrated, 
as opposed to a purified, condition; their outstanding and indeed remarkable 
property is their very highly specific character. In every instance their action 
is restricted to one or to a few substances very closely related in structure, 
and there is obviously the most intimate correlation between the structure of 
the substrate and of the enzyme complex. 
Enzymes behave essentially as particulate colloids in an extremely fine 
state of division, and as such are naturally very unstable or, in other words, 
susceptible to outside influences. Their great activity as catalysts is due to this 
development of active surface, enzyme action taking place essentially at solid 
surfaces and not in solution; the older phrase ‘ soluble enzymes’ is a misnomer. 
Under ideal conditions, when the influence of secondary changes and of the 
products of action is eliminated, the rate of change conditioned by enzymes 
is such that equal amounts of substrate are changed in successive equal intervals 
of time. 
Taking into consideration the intimate structural relationship between enzyme 
and substrate, there is every reason to assume that change is preceded by.the 
formation of an unstable intermediate complex with the substrate at the surface 
of the colloid enzyme, the attractive force being chemical; the alternative 
theory pictures adsorption at the active surface, the layer being at most little 
more than one molecule thick and the attractive force being physical. The 
difference between the rival theories is practically only one of phraseology. 
Subsequent action in which the activated water molecules take part results 
in the breakdown of the intermediate complex in all possible ways. 
We have still to form a clear mental picture of how the energy necessary to 
effect this is derived. This problem, however, is primarily one for the student 
of the processes operative in solutions. 
12. Dr. K. G. Farx.—The Relation of Certain Enzyme Actions to 
Tissue Differentiation and Tumour Growth. 
The comparative lipase actions on a number of different esters and protease 
actions on several protein preparations, of different tissues and organs of rats 
as well as of the Flexner-Jobling rat carcinoma, were studied. Well-defined 
differences in the actions were found. A number of tumours of human origin 
and some normal human tissues were studied similarly. In general, the tumours 
showed the same comparative lipase actions on the different esters. These 
relative actions were similar to the relative actions found with the Flexner- 
Jobling rat carcinoma. A more complete study of the enzyme actions of 
fibromyoma of the uterus indicated in some cases enzyme actions similar to 
those of the rat carcinoma and other tumours, in other cases enzyme actions 
of the growths similar to those of uterus muscle, and in some cases both types 
of actions present in the material obtained from different parts of the same 
specimen. The enzyme results corresponded to the histological examinations of 
the same materials. The absolute amounts of the enzyme actions of the tumours 
of various origins were small in comparison with the enzyme actions of some 
of the tissues. The significant differences were found to be in the characters 
of the actions rather than in their magnitudes. 
The materials for the enzyme tests were prepared by extraction with water — 
after suitable grinding. The solid residues were also tested in a number of 
experiments. The enzyme actions were determined ynder comparable conditions. 
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