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.

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    C'hittt'iulen has shown that, the broiiiclin and the ronnctt fernu'nt which are both present in the juico of the pineapple are probably associated with two definite proteids, thongh he does not assert that either enzyme is identical with such proteid. Bromelin, the proteolytic enzyme, always occurs in close connection with a proteid which exhibits most of the characters of a proto-proteose. It is precipitated from a neutral solution by saturation with either ammonium or magnesium sulphate, or with sodium chloride. It is soluble in water and consequently is not precipitated by dialysis. It is further not coagulated by long contact with strong alcohol, and its aqueous solution is very incompletely precipitated by heat. In its behaviour towards nitric acid and heat and in some other ways it does not show^ the typical proteose reactions, and it contains a smaller amount of nitrogen than most proteids. The rennet enzyme is more closely associated with a body whose reactions agree in the main with those of hetero-proteose. It is less soluble in water, requiring for complete solution a little neutral salt. It is more completely precipitated by heat than the proto-proteose described. The closeness of this association in both cases may possibly indicate that these proteids are actually the enzymes in question, but the identity cannot be considered conclusively proved. Lintner prepared diastase in what he considered to be a pure condition, and from the results of analyses of his pre- paration he concluded it to be a proteid, but not one of the ordinary class. He found that it contained only two-thirds as much nitrogen as, and less carbon than, the latter. It differed also in not giving the biuret reaction. Lintner hence suggests that the enzymes constitute a special class of proteids. Buchner associates his new zymase with a proteid in the yeast which is coagulated at 45° C. At this temperature the zymase also is destroyed. When this proteid has disappeared from the extract in consequence of the action of the proteolytic enzyme of the yeast, the power of producing alcohol is lost. Buchner does not however claim that the proteid is the zymase. None of the researches quoted can be considered to go very