April, 1946
COMMUNICATIONS -ro THE EDITOR
725
D-ribonate tetraacetate (m. p. 87-87.5', [LY]~'Ddata indicate a molecular volume increase on the + 1 7 O in chloroform), after removal of catalyst order of 50 cc. or more per mole, although an and solvent, was crystallized from acetone- accurate value requires detailed data on the rate methanol-(petroleum ether) and yielded ddehydo- of the reaction a t different pressures. Pressures of this magnitude oppose the reversible D-ribose tetraacetate2 in rather low yield. Full details will be reported in a latter com- and irreversible denaturations of certain enzyme systems2 and greatly retard the denaturation of munication. purified human serum globulin a t 65°.3 These (2) R. Pasternack and E. V. Brown, U. S. Patent 2,237,263 (1941). pressure effects are considerably greater than those encountered with reactions of small moleCHEMICAL LABORATORY THEOHIOSTATE UNIVERSITY M . L. WOLFROM cules and indicate that a number of groups are COLUMBUS, OHIO J. V. KARABINOS involved, or perhaps the protein molecule as a RECEIVED FEBRUARY 25, 1946 whole. They suggest that changes as extensive as those which take place in denaturation occur also in specific precipitation. An extensive PRESSURE AND SPECIFIC PRECIPITATION quantitative study of pressure effects on the rate Sir: of specific precipitation will perhaps yield cogent Although th'e reactions that lead to specific data regarding the mechanism of the reaction. precipitation evidently involve a combination be- THEGATESAND CRELLIN DANH. CAMPBELL tween a di- or polyvalent antigen or hapten and LABORATORLES FRANK H. JOHNSONP OF CHEMISTRY specific sites on the antibody protein, probably CALIFORNIA INSTITUTE OF TECHNOLOGY CALIF. resulting in the formation of a framework com- PASADENA, RECEIVED FEBRUARY 6, 1946 prising large aggregates of the two species of molecules, convincing evidence is lacking as to (2) Johnson, Eyring, Steblay, Chaplin, Huber and Cherardi, J . whether the protein itself becomes significantly Gcn. Physiol., as, 463 (1943). (3) Johnson and Campbell, J . Cell Cornp. Physiol , 26,43 (1945). altered in the process. The following observa(4) Guggenheim Fellow. tions bear on this question and suggest an approach for further study. The precipitation system consisted of serum METABOLIC PRODUCTS OF ASPERGILLUS USTUS from rabbits immunized against arsanilic-azo- Sir: Publication of preliminary results by Hogesheep serum and a simple trihaptenic dye antiboom and Craig' on the application of the latter's gen, viz.
N I =x~-N=N-(T / / oT ) - ~ ~ o H \OH
To slow the precipitation for practical purposes, the serum was diluted 1:2, and the antigen 1:160,000. Visible precipitation occurred within a few minutes, and went to about three-fourths completion in an hour a t room temperature. Small test-tubes were filled with corresponding specimens, stoppered with a rubber 'stopper, then placed in a water-filled steel pressure chamber, and hydrostatic pressure applied from a hydraulic pump within one to two minutes after mixing. At 10,000pounds per square inch a scarcely visible precipitate formed during slightly more than an hour. After the pressure was released, precipitation continued in apparently the normal manner. Lower pressures were less effective, but quantitative analyses of protein nitrogen in precipitates centrifuged within less than five minutes after releasing pressure, showed decreases ranging from 55 to 77% under pressures between 1,500 and 8,000 pounds, in comparison with the Amount under normal pressure. These (1) Pauliny. Camphell and Pressman. Physrol 11943).
R e v , 23, 203
countercurrent distribution method to the problem of isolating bacteriologically active components from the culture filtrate of Aspergillus Ustus2 prompts us to report briefly the progress of our work carried out in collaboration with Mr. Joseph Kurung and Dr. Harry Bray, Superintendent of the New York State Hospital for Incipient Tuberculosis. The crude active obtained by ether extraction of the culture filtrate or mycelium, has been divided into a bicarbonate soluble, a carbonate soluble and a neutral fraction. By fractional crystallization three substances have been isolated from the neutral fraction in small, variable amounts, and never all three from a single sample of crude material: A.U.N.-I, m. p. 1556') (C, 38.24; H, 4.10; C1, 23.87); A.U.N.-?, m. p. about 270' with severe decomposition, inadequately characterized a t present; A . U . N . 3 , (1) Hogeboom and Craig, J . Bioi. Chcm., 161, 363 (1946). (2) Kurung, Science, 102, 11 (1945). (3) Generously supplied to us by Mr. Joseph Kurunp and the Wallerstein Company, Inc.
726
COMMUNICATIONS TO THE
EDITOR
Vol. 68
in. p. 225.5-226.5’, (C, 62.59; H, 4.81; C1, 8.59). pounds, such as long chain fatty acids, can form The carbonate soluble fraction consistently has monomolecular films on water and that the areas given the predominant active component which of such films can be related to the dimensions of we are naming ustin. This material may be the molecules.2 Certain polymeric substances purified by fractional crystallization from tolu- including cellulose derivatives, proteins4 and the ene, acetic acid, ether, or ether-hexane, m.p. polymer of w-hydroxydecanoic acid5 likewise form 184-186’. The probable empirical formula of stable films whose areas can be conveniently ustin, C1SH1SOSC13, is consistent with the analyti- measured.‘j At this time we wish to report that cal results (C, 63.42; H, 3.69; C1, 24.27), con- we have prepared films of some rubber-like polyductometric titration (N.E. 214), and the ele- mers as well and that the results appear to give ment ary composition of the monomethyl deriva- useful information about their molecular structive, m. p 174’ (C, 54.09; H, 3.95; C1, 23.54; tures, particularly in relation to branching. CH30, 7.0 l),the dimethyl derivative, m. p. 147’ Five ml. of a very dilute benzene solution of a (C, 55.00; H, 4.24; C1, 23.19; CH30, 13.35), polymer (c = 2 X g./ml.) is distributed over and the acetyl derivative, m. p. 212’ (C, 53.68; the water surface of a hydrophil balance. After H, .‘1.95; C1, 22.76; CH30, 9.67). Compound the benzene has evaporated, the film area is I isolated by Hogeboom and Craig,’ m. p. 185- measured in the usual manner.’ Low conversion 187’, is probably identical with ustin4 although samples of GR-A (butadiene;atrylonitrile cothe large discrepancy between our chlorine analy- polymer) gave films about 6 A. thick whereas sis and that obtained by Hogeboom and Craig high conversion samples exhibited thicknesses as iC1, 22.G.3:i suggests that their compound is im- great as 30 A. It is our belief that a large film pure even though isolated by the elegant counter- thickness indicates a high degree of branching and current distribution method. that the corresponding polymer molecules can be The antimicrobial activity of ustin, A.U.N.-1 , better represented as “bottle brushes” than as and A.U.X.-2 are indistinguishable by any of the straight chains. Other polymers containing hyin vifro tests used so far. I n synthetic media, the driphilic groups have also been investigated; these compound; inhibit the growth of Gram positive include copolymers of butadiene with methacrylococci and mycobacteria (including pathogenic nitrile, 1-cyanobutadiene, m-fluorostyrene and tubercle bacilli) to the same degree, but are inac- some vinylpyridines. tive against Gram negative bacilli. Their antiStable films for polymers such as natural rubseptic activity increases rapidly with the H + ber or GR-S could not be obtained directly. Howconcentration of the environment, but is sharply ever, these substances can be investigated by the inhibited by the addition of serum albumin, and film technique if they are first rendered hydroof certain other organic substances (lipids for philic by the addition of thiocyanogen to some of example) to synthetic media. Thus any one of the the double bonds according to the methods of compounds can exert an inhibitory effect on the Pummerer and Stark and of liehner.8 ;Ifter growth of tubercle bacilli, streptococci or sta- using their procedures, we found natural rubber phylococci in a dilution of 1/500,000 a t pH 6.5 in a and gutt? percha to form relatively thin films simple synthetic medium, but will fail t o retard growth even in 1/50,000 in more complex media a t (about 8 A. thick) whereas the film thicknesses of GR-S exhibited wide variations with polymer slightly a1kaline reactions. We wish to express our sincere appreciation to conversion, indicating once more marked differDr. Adalbert Elek for the excellence of his micro- ences in branching. On the whole, the method appears to show analytical assistance. The details of this work will be published considerable promise as a tool for learning more about the structure of polymers. shortly * SOYES CHEMICAL LABORATORY UNIVERSITY OF ILLINOIS FREDERICK T WALL ILLINOIS MURRAY ZELIKOFF UT E DOFRIW YRBANA, R J. D U B 0 5 RECEIVED FEBRUARY 18, 1946
(4) Dr Craig very kindly examined t h e melting points a n d found n o depression i m p a n d mixed m p 186-188O)
DEPARTME\ T OF CHEWISTRY COLUMBIA IJNIVERSITY AND DEPARTME\ T OF B.4CTERIOLOGY ROCKFFELLCR IhSTITUTE
D s SOYCE R DREY~US
SEW YORK N i x YORK
R E C ~ I V EMARCH D 8, 19-16
SURFACE FILM THICKNESSES OF POLYMERIC SUBSTANCES IN RELATION TO MOLECULAR STRUCTURE’
Sir: It is gt:nerally well known that Certain com,l) ’The work reported in this letter was done in connection with t h e Guvernmitnt research program on s y n t h e t i c r u b b e r under cont r a c t w i t h t h e Office of R u b h e r Reserve, Reconstruction F i n a n r e Ccirp
