The protein constituents of egg white.

  • Osborne, Thomas B. (Thomas Burr), 1859-1929.
Date:
[1900]
Catalogue details

Licence: In copyright

Credit: The protein constituents of egg white. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    after heating for some time at 88° and when washed and dried gave 3.5 grams of D.3.2. The filtrate from this gave no more coagulum on heating and after dialyzing free from chlorides was concentrated to small volume and precipitated by pouring into alcohol. This gave us 2.0 grams of D.3.3. Seven grams of F.3 were dissolved in 280 cc. of 5 p. c. brine and the solution heated to 67°. The flocculent coagulum, which began to separate at 590, was filtered out, washed and dried, giving 1.87 grams of F.3.1. The filtrate heated to 920 gave another coagulum which began to separate at about 70°. This, when dry, weighed 2.17 grams, F.3.2. The filtrate from F.3.2, dialyzed free from chlorides and precipitated by alcohol, gave 1.39 grams of F.3.3. Twenty-five grams of K.3 (the more soluble part of a preci- pitate obtained by adding an equal volume of saturated' ammonium sulphate solution to a large quantity of egg white) were dissolved in about 800 cc. of 10 p. c. brine, the solution filtered clear and heated to 6o°. The coagulum was washed with salt solution, suspended x in water after passing through fine bolting cloth to break up all lumps, washed thoroughly with water, and with alcohol, and was dried, giving 2.78 grams of K.3.1. Unlike ovalbumin, this coagulated proteid separated in a finely divided state, so that it could be easily washed through the cloth. The filtrate from this coagulum was dialyzed free from chlorides and then evaporated to dryness below 6o°, leaving a residue which weighed 17.2 grams and had a specific rotation °f 37°-55/- This rotation being much greater than that of ovalbumin, the whole of this residue was dissolved in 10 p. c. brine, the solution heated in a boiling water bath, the coagulum, K.3.2, filtered off, the filtrate dialyzed free from chloride and the clear solution poured into alcohol. The substance, K.3.3, thus precipitated, weighed dry, 1.39 gram, and consisted of ovomu- coid as shown by its rotation, 6i° 30'. I he preparation K.3 was prepared from the precipitate pro- duced by half saturating the egg white solution with ammo- nium sulphate, which precipitate is commonly supposed to con- sist almost wholly of globulin. Nevertheless our results show that K.3 contained about 11 p. c. of the albumin coagulating below 65°, 83.0 p. c. of ovalbumin and over 5 p. c. of ovomucoid.