The effect on the molecular concentration and electrical conductivity of muscle extracts of removal of the proteids / by G.N. Stewart.

  • George Neil Stewart
Date:
[1899?]
Catalogue details

Licence: Public Domain Mark

Credit: The effect on the molecular concentration and electrical conductivity of muscle extracts of removal of the proteids / by G.N. Stewart. Source: Wellcome Collection.

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    quantity of a globulin coagulating at 56°, an additional proof that the two globulins are chemically different bodies would be afforded; and the same for substances whose coagulation temperatures lie closer together. It will be seen from the results subjoined that distinct differences were made out in the conductivity after removal of the proteids, the conductivity being increased. In Exp. 3 the increase after removal of '2378 grm. proteid from 100 c.c. of a magnesium sulphate extract was from 72*49 to 76'41 or 5'4 p.c. (=22*7 p.c. per grm. of proteid); in Exp. 4, after removal of *3818 grm. proteid from 100 c.c., the increase was from 113'0 to 117'0 or 3*5 p.c. (=9*2 p.c. per grm. of proteid); and in Exp. 5, after removal of *5739 grm. proteid, the increase was 1*4 p.c. (=2*4 p.c. per grm. of proteid). In the same experiment the removal of *2033 grm. of proteid coagulating between 60° and 100° caused an increase in the conductivity of 1*9 p.c. (=9*5 p.c. per grm. of proteid). The removal of all the proteids from the cooled plasma of frog’s muscles (Exp. 1) caused an increase of 10*2 p.c. The resistance measurements are too exact to permit us to suppose that the apparent increase is due to errors of measurement. If it is due merely to the elimination of the well-known depressing influence (molecular friction) of dissolved non¬ conducting substances on the conductivity of electrolytes, apart from chemical or physico-chemical combination with them, the globulins of muscle extracts must depress the conductivity in a much greater degree than the proteids of serum or haemoglobin. For Bugarsky and Tangl1 found that 1 grm. of proteid, prepared by long-continued dialysis from blood-serum, depressed the conductivity of 100 c.c. of serum by only 2*5 p.c.; and I found for 1 grm. of haemo¬ globin in 100 c.c. of serum a depressing effect of no more than 1*8 p.c.2 It seems necessary to suppose then, that a certain portion of the magnesium sulphate is combined with the proteids, or at least is so affected by them that its dissociation coefficient (the number which measures the extent to which it is dissociated) is diminished. Liebermann and Bugarsky3 have recently stated that egg-albumin, albumose and pepsin do combine with sodium hydroxide, and hydro¬ chloric acid, bat not with sodium chloride. It might be expected that the globulins, which are only dissolved by the aid of neutral salts, would 1 Pfliiger’s Archiv, lxxii. S. 540. 1898. 2 This Journal, xxiv. p. 216. 1899. 3 PJIUger’s Archiv, lxxii. S. 51. 1898. 22500887145 WELLCOME INSTITUTE LIBRARY Coil. wokv'Omec P-'j ! Ul!i* p-m No. we soo / g S 81? e II
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