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ENZYMES. 63
that the adsorption process is only reversible with great difficulty or
that the enzyme to a certain extent is fastened to the charcoal. That
the substrate influences the formation of adsorption combination is
shown by the fact that the substrate is also adsorbed by the charcoal.
A small part of the adsorbed enzyme can indeed be subsequently
displaced on the charcoal by other adsorbable. substances and in this way
become active again. As various substrates are unequally adsorbed
by charcoal the retardation is, therefore, also different in degree. The
retardation of the saccharase action by charcoal is the same as for the
retardation of the trypsin or rennin action (Eriksson j
).
The action of several enzymes is retarded by normal serum. This
was first observed by Hammarsten and Roden 2
for the action of rennin.
Besides this certain constituents of the serum as well as other protein
containing fluids have a retarding action and in many such cases the
order of the addition of the bodies is important. The retardation by
charcoal corresponds to this retardation in several ways and this has
led Hedin 3
to the assumption that the retardation in both cases is brought
about by a colloidal reaction (adsorption) between the enzyme and a
solid or colloid phase. The facts correspond to this assumption namely
that during the action of the retarding substance upon the enzyme
the amount of water present is without importance for the final result
of retardation. Such a retardation by normal serum or fluids con-
taining protein has been observed in the following cases: retardation of
trypsin digestion of casein by native seralbumin,4
retardation of the action
of rennin by neutral serum and by white of egg,5
and the action of sac-
charase by serum.6
Besides this Hedin 7
found a similar retardation by
seralbumin upon the digestion of casein by means of the a-protease of the
spleen. The retardation by normal serum or seralbumin has been shown
in the cases investigated not to be a specific kind, i.e., a given enzyme
is retarded about to the same extent regardless from what species of
animal it was prepared.
A specific retardation due to kind have been observed in the following
cases
:
1. The antienzyme obtained by immunization (see page 66) retards
in those cases tested, only or chiefly the enzyme used in the immuniza-
l
Ibid., 72, 313 (1911).
2
Upsala lakarefor. forh., 22, 546 (1887).
3
Bioch. Journ., 1, 484 (1906); Zeitschr. f. physiol. Chem., 60, 364 (1909); Ergebn.
d. Physiol., 9, 433 (1910).
* Journ. of Physiol.. 32, 390 (1905); Bioch. Journ., 1, 474 (1906).
5
Zeitschr. f. physiol., 60, 85, 364; 63, 143 (1909).
6
Ibid., 72, 313 (1911).
7
Hammarsten’s Festschr., 1906.
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