of 0.01 Jf salt which has been previously shown t o suppress metachromasv also suppresses dye binding measured by equilibrium dialysis. This would indicate two different niechanisiiis of suppression of metachroinasy. Froin the results of our previous work, we believed that high chromotrope concentrations destroyed metachromasy by acting as a salt. I~quilibriuin dialysis experiments indicate t h a t this idea may not be correct. Of particular interest in looking for a connection between tlye binding and inetachroiiiasy is the case of methylene green, a (1)-e similar t o methylene blue but showing almost no deviations from Beer’s law and almost n o metachromatic effect. In equilibrium dialvsis the extent of its binding bv chondroitin sulfate is only about 30y0 of that of methylene blue or crystal violet as indicated by the ratios in the last column of Table 11. The extent to which methylene green becomes concentratetl in the bag may be considered as a measure of the Uonnan effect. The increased concentration effect with methylene blue or crystal violet over that of methylene green may then he a ineasure of the binding of these dyes by chromotrope. The work of Kurnick and ,lIirskyE using dialysis shows binding of methyl green bv desoxyribonucleate. llethyl green, a close relative of crystal violet, also obeys Beer’s law and seems to show no metachromasy. Another factor which must be considered in the interaction of dye and chromotrope is the formation of precipitates such as t h a t of toluidine blue by h e ~ i a r i n . ~This precipitation occurs at dye and chroniotrope concentrations higher than those used in the present study. I t is important to note that the tlye-chromotrope complex prepared in our laboratory, when washed and redissolved in water, does iiot produce a mctachrotnatic spectrum hut one ?I i ‘ U Kurnick and A 12. hlir$ky, J Celt Phy.riui 33, 20: f l ‘ I i 0 ) H J ~ i q i r e \ 8zsrhrwi I 37, 189 ~ l ‘ I l 3 1
Y> I
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similar t o t h a t of a dilute toluidine blue solution. This precipitate of dye and heparin thus has spectral properties which may account for the rise in the a- and p-bands of metachromatic dyes at high cliromotropic concentrations. It might be assumed that two separate conditions of the dye can exist which produce the same spectrum. I t seeins possible to correlate the metachromatic properties of polysaccharides and detergents in the inore dilute solutions, as follows. Xt chromotrope concentrations 1 0 P and below there is no marked evidence for interaction between tlye and chromotrope. At these low concentrations the individual polysaccharide molecules are assumed to be linearly disposed ant1 the detergent molecules to be separated and ionized. I n the concentration range from l W Gto about 1W4where a- a n d @-bandsare depressed and p-bands rise, it is assumed that micelle forination of the chromotropes occurs to Irotluce i n the solution micro regions of high anion density. The occurrence of such micelles in soap solutions has been extensively studied and the critical concrntration of micelle forination has been f o ~ n t l ~ ~ ~ ~ for various soaps to lie in the range from to 0.3 M . The work of Fuoss and Strauss” similarly indicates that high molecular weight linear polyelectrolytes change their molecular shapes with increasing concentration from one of extended chains to one of highly folded or coiled chains. Thus, in more concentrated solutions of both anionic detergents and polysaccharides, micellelike configurations seem to be formed. Such micelles may account for the results of both metachromatic and dialysis experiments though the mechanism is still obscure. (10) A W Ralston, A n n V Y Acnil S c i , 46, 351 (1036J. i l I ) I< &I I i i i i , i \ and IJ P Strdii\\, % b i d ,51, 836 (1919).
Yr,w YORKIC,, IC,Y
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[CONTRIBUTION FRO11 THE 1)EPARI;MENT O F CHEMISTRY, c S I V E R S I T Y OF
ISCO CONS IN]
The Conversion of Fibrinogen to Fibrin. X. Light Scattering Studies of Bovine Fibrinogen BY
SIDXEY KATZ,KURTGUTFREKJND, S I D N E Y SIIULMAN
AND JOHN
D. FERRY
RECEIVED JIJNB 5 , 1952 Light scattering measurements have been made on solutions of bovine fibrinogen, using two types of purified fractions and three different solvent compositions. The angular scattering distribution was measured in a conical cell, and the dissymmetry and absolute intensity were measured with high precision in a semi-octagonal cell. From the
