August, 19(i0
SOTES
the optical densities of the solutions containing the phenol a t pH 2 aiid 12, respectively, and D the optical demity of the buffer solutioiis with the phenol. The resultant pK values 5.45 and 6.46 may be compared with those calculated on the assumption that chloro and nitro substituents have additive effect,s on the pK of phenol; from the data of .Judson and Kilpatrick4on monosubstituted phenols we calculate pK 5.67 aiid 6.66, respectively. TABLE I IOSIZATIOS (l. J. WISZORA A D J. AI. CREETH Drpaitment of I'hjstcal a n d I n o r g a n i c C h e m i s t r y , S o u t h Australia Rrceired M a i c h A 1960
I - i i 7 i e i \ ~ t l / of.'tfir1o?de,
Procedures for the determination of heterogeneity from diffusion measurements on mixed solute systems have been shown to be valid for dilute solutions of simple substances such as sucrose a i d urea and have been applied to a fern proteiii systems.'-' Deviations from "ideal" diffusion hehavior in a manner indicative of heterogeneity have been observed in all protein systems studied, the deviations generally being represented in terms of fringe deviation diagrams.2,4 However, analysis by t,hese procedures assumes independence of flow of each solute component: in a previous comC . Ogston, Proc. Rou. S a c . (London). A196, 2 i 2 (1949). ( 2 ) D. F. Alie1e.p and L. J. Gosting, J . A m . C h e m . Foe., 76, 5GSn
(1) A.
(1953).
(3) J. M. Creeth and L. J. Gosting, THISJOVRXAL,62, 58 (19.581. (4) J. .\I. Creeth, ibid., 62, 60 (1958). (5) R. L. Baldwin, L. J. Gosting, J. 13'. Wi1liam.q and R Disc. Faraday Sor.. 20, 13 (1955). (6) I. J. O'Donnell, R. L. Baldwin and J . W. \$-iliiams, Biochim. Biophys. Acta, 28, 294 (1958). ( 7 ) J. hl. Creeth, L. W.Nichol and D. J. Winzor, THISJOURNAL,62,
154lj (1958).
