Feb. 5 , 1953
COMMUNICATIONS TO THE EDITOR
appears reasonable that the mechanism whereby pyridine prevents complete substitution of Poc13 to R3P0 involves an effective reduction in Grignard reagent concentration, probably by association with RMgX. The suggestion that phosphonic acids may be produced in better yield by using larger proportions of pyridine at lower temperatures6 may be valid, but not because of blocking C1 atoms in POC13. Work has been started in this Laboratory to study quantitatively the effect of bases on Grignard reactions involving POC13 and related compounds. The work with pyridine and a-picoline indicates that POC13 probably does not form quaternary salts with any pyridine bases. Actually, com-
753
pounds have been isolated between POC4 and acids such as SO3l7 and SnC&.'* In light of the results obtained with pyridine bases, formula I, may be considered a more likely structure than formula 11. An incidental result of the present work is that doubt is cast on the postulated reaction mechanism in a recent paper,lg which requires quaternary compound formation between POCh and a pyrazine derivative. (17) G. Oddo, Coss. chim. M . , 17, 29 (1927). (18) S. Sugden and H. Wilkens J . Chem. SOC.,1291 (1929). JOURNAL, 74, 1580 (1952). (19) G. Karmas and P. E. Spoerri, THIS
CHEMICAL CORPSCHEMICAL AND RADIOLOGICAL LABORATORIES ' ARMYCHEMICAL CENTER, MARYLAND
COMMUNICATIONS T O T H E E D I T O R THE NATURE OF THE XANTHINE OXIDASE FACTOR
revealed that the ingestion of molybdate ion is responsible for the increased xanthine oxidase A factor(s) in liver residue and soy flour which levels. The addition of as little as 1 mg. of sodium increases the level of liver and intestinal xanthine oxidase when fed to weanling rats has been des- molybdate/kg. diet or the injection of 107 subcribed by Westerfeld and R i ~ h e r t . ' * ~An * ~ ex~ ~ cutaneously gave values for xanthine oxidase equal cellent assay for this factor utilizing rat intestine to that obtained when 10% liver residue was fed. also has been described by these author^.^ How- Table I shows some typical data. Preliminary ever, the nature and mode of action of this sub- studies indicate that no other element is able to replace molybdenum and the highly specific nature stance(s) is unknown. During the course of fractionation studies on of this effect is therefore apparent. liver residue it was found that the xanthine oxidase TABLEI factor(s) could be partially liberated by autoclaving EFFECTOF LIVER RESIDUE,LIVERRESIDUEFRACTIONS in water. The activity of the extracts so obtained AND MOLYBDATE ION ON RAT INTESTINAL XANTHINE was found to be dialyzable and stable to severe OXIDASE VALUES acid or alkaline treatment. Average X. 0. value, c.mm.Q uptake/ When liver residue or extracts from liver residue unit time/unit wgt. Supplement added to basal diet/kg. of intestine were ashed, the activity, surprisingly enough, was found to be unaltered. The inorganic material None 4.4 so obtained, when assayed spectrographically,0 10% liver residue (LR) 25.6 LR 32.0 was found to contain many elements among which Liver residue extract (LRE) ~ 1 6 % 28.2 were Al, Sb, Ba, B, Cr, Co, Pb, Mol Nil Ag, Sn, Ash of LR 10% LR 26.9 Ti, V and Zn. The more "common" elements such Ash of LRE * 20% LR 5.1 as K, P, Na, Cu, Fe, Si, Mg and Mn were also Dialyzed LRE * 20% LR 23.5 present. In addition, the activity of liver residue Sodium molybdate, 1 mg. or its ash could be replaced by including a suppleTo our knowledge, this represents the first report ment of Hoagland's A-Z solution7in the diet of rats. Further investigation with single salt supplements suggesting an in vivo role for molybdate in an animal enzyme system. The possible importance (1) W. W. Westerfeld and D. A. Richert, J . Biol. Chem.. 184, 163 of this finding on the role of molybdenum in animal (1950). nutrition is of course obvious. Studies are now in (2) W. W. Westerfdd and D. A. Richert, Science, 109, 68 (1949). progress to elucidate the precise role of molybdenum (3) W. W. Weaterfeld and D. A. Richert, Proc. SOC.Exfl. Bid. Med., 71, 181 (1949). on the activity of xanthine oxidase.
Sir:
(4) W. W. Westerfdd and D. A. Richert, J . B i d . Chcm., 199, 35 (1951). (6) D. A. Richert and W. W. Westerfdd, ibid., 199, 49 (1961).
E. C. DE ~ N Z O E. KALEITA LEDERLE LABORATORIES DIVISION P. HEYTLER (6) We M indebted to Mo.W. L. Dutton and hia itaff of the StamAMERICANCYANABZID COMPANY J. J. OLESON ford R-h Laboratoriu, AmericPn Cyanamid Co.,for the spectroPEAFU RIVER, NEWYORK B. L. HUTCHINGS mPMc 4JRL. J. H. WruJIlas (7)D.R. Hoagland and W. C. Snyder, Proc. A m ? . Soc. &?or#.Sd., R S c p r v S D J W A R Y 21,106a m, asa (ma).
