The soluble ferments and fermentation.

  • Green, J. Reynolds (Joseph Reynolds), 1848-1914.
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: The soluble ferments and fermentation. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

    418/504 (page 398)
    A more striking fact is that the temperatures at which so many enzymes are destroyed correspond very closely to the points at which proteids occurring with them are coagulated. Most of the methods of preparation which have been de- scribed are such as would throw proteids out of solution. Two very prominent means of precipitating enzymes we have seen are the addition of excess of alcohol to the solution, and its satura- tion by neutral salts. These methods precipitate the proteids, and the enzymes are thrown down with them if any are present. The experiments do not show whether the proteid and the enzyme are identical, or whether the latter is merely mechanically associated with the former. It is remarkable however that prolonged exposure to strong alcohol coagidates the proteids, and that the same treatment gradually destroys the power of the enzymes. In some cases observers have found the association of a particular enzyme and a certain proteid to be so constant and so close that they have been led to the view that the two are identical. Osborne has studied the association of diastase with proteids in the cereals, wheat, rye, and barley. In them all he has found an albumin which he has named leucosin, besides a globulin and a proteose. All ferment extracts which he prepared from any of these cereals contained a mixture of these proteids, but when they were separated by various methods the greatest diastasic power clung to the leucosin. The proteose was found to be associated with a certain proportion of the enzyme, but much less than the leucosin. The quantity of leucosin and the fermentative activity also varied together, though not with very great exactness. As the result of his experiments Osborne came to the view that the diastase is either the leucosin or a compound of the latter with some other body, presumably the proteose ; and that this compound breaks up on being heated and yields coagulated albumin, some free albumin being coagulated at the same time. The view cannot be considered proved, as certain of his solutions which contained only the proteose possessed a certain, though relatively feeble, diastasic power.