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.

    17/28 (page 365)
    Elementary Composition. In the following table we give the analyses of our four purest preparations of ovalbumin, and also analyses of two preparations made by Hofmeister’s method as described on page 366: Composition of Ovalbumin. B.l, B.2. C.l. C.2. No. 2. No. 3. Average. Carbon 52-59 52-73 52-75 52-79 52-82 52.78 52.75 Hydrogen 7.10 7-og 7-31 7-00 7.03 7.07 7-10 Nitrogen 15-55 15-57 *5-50 15-60 15.32 15-53 *5-51 Sulphur 1.613 1.619 1.613 1.634 1.590 1.651 1.620 Phosphorus __ 0.126 0.127 0.131 0.126 0.123 0.112 0.122 Oxygen 23.021 22.814 22.696 22.850 23.117 22.857 22.898 100.000 100.000 100.000 100.000 100.000 100.000 100.000 Analytical Methods. Carbon and hydrogen were determined by using an open tube with copper oxide, lead chromate and metallic copper, and finishing the combustion in oxygen. Nitrogen was determined by Dumas’ method, the air being removed by a Sprengel pump, the tube then filled with carbonic acid set free by heat- ing sodium bicarbonate at the front end again, emptied by the pump and this process repeated. In this way all the air was removed and no fixed gas was driven off on heating the reagents. Nitrogen was also determined by the Kjeldahl method and results in close accord with those of Dumas’ method were obtained. Sulphur was determined by fusing about one gram of the substance with sodium hydrate and peroxide over an alcohol lamp. The reagents were proved to be free from sulphur. Phosphorus was determined by fusing about one gram of the substance with sodium peroxide, dissolving the fusion in nitric acid, precipitating with molybdic solution and weighing as magnesium pyrophosphate. The figures given in the above table agree well with those of others who have prepared and analyzed ovalbumin with especial care, as may be seen in the following table: Composition of Ovalbumin. C. H. N. S. P. 0. Hammarsten 52-25 6.90 15-2 5 1-64 23.69 uncoag. Chittenden & Bolton .. 52.33 6.98 15-89 1.83 22.97 “ 5233 6.98 15-84 1.81 23.04 coag. Bondzinski & Zoja 52.39 7.11 15.39 I#66 23.45 “ Osborne&Campbell .. 52.75 7.10 15.51 1.62,0.1222.90 HoPkins 52-75 7-12 15.43 i-57