Scientia Sinica

90 SCIENTIA -SINICA Vol, V

procedure which involves adsorption on calcium phosphate gel and repeated fractionation with ammonium sulphate at low temperatures. The final preparation obtained is almost electrophoretically pure and has a specific activity of about 40 times that of the heart muscle preparation and nearly 200 times that of a heart muscle homogenate.

2. The effects of temperature, substrate concentration, acceptors and other factors on the enzyme activity have been studied.

3. The purified enzyme is a metalloflavoprotein containing non-haematin iron. An analysis of the purified enzyme gives a ratio of 140,000-160,000 grams of protein to 1 gram-molecule of flavin or 4 gram-atoms of iron.

REFERENCES -

[1 1 Wang, Ying-Lai, Tsou, Chen-Lu, and Wang, Tsing-Ying. 1955. 3rd. Int. Congress of Biochem. Brussels. -

[2] Tsou, Chen-Lu, 1951. Biochem. J.,49, 512. -

[3] Bach, S. J, Dixon, M., and Zerfas, L. G., 1946, Biochem. ]., 40, 229.

[4] Ball, E. C., Anfinson, E. B., and Cooper, C., 1947. J. Biol. Chem., 168, 257.

[5] Pappenheimer, A. M., and Hendee, E. D., 1949. J. Biol. Chem.,180, 597.

[6] Chance, B., 1952. J. Biol. Chem.,197, 567. —

[7] Axelrod, A. E., Potter, V. R., and Elvehjem, C. A:, 1942. J. Biol. Chem., 142, 85. [8] Wang, Tsing-Ying, and Wang, Ying-Lai (unpublished results).

[9] Morton, R. K., 1950. Nature, 166, 1092.

[10] Neufeld, H. A., Scott, C. R., and Stotz, E., 1954. J. Biol. Chem., 210, 869.

[11] Singer, T. P., and Kearney, E. B., 1954. Biochem, Biophys. Acta, 15, 151.

[12] Singer, T. P., Kearney, E. B., and Zastrow, N., 1955. Biochem. Biophys. Acta, 117, 154:

[13] Singer, T. P., and Kearney, E. B., 1955. Fed. Proc., 14, 282.

[14] Tsou, Chen-Lu, 1952. Biochem, J.,50, 493.

[15] Tsou, Chen-Lu and Li, Wen-Chieh, 1955. Acta Physiologica Sinica, 19, 361. |16] Negelein, E., and Bromel, H., 1939. Biochem. Z.,300, 225.

[17] Kunitz, M., and Northrop, J. H., 1936. J. Gen. Physiol., 19, 991.

18] McDonald, M. R., and Kunitz, M., 1946. J. Gen. Physiol., 29, 155.

[19] Tsou, Chen-Lu, 1951. Biochem. J., 49, 362.

[20] Stocken, L. A., 1947. J. Chem. Soc. 952.

[21] Straub, F. B., 1938. Nature, 141, 603.

[22] Keilin, D., and Hartree, E. F., 1937. Proc. Roy. Soc. B, 124, 397.

[23] Kehrmann, F., und Havas, E., 1913. Ber., 46, 343.

[24] Smith, R., Bullock, J. L., Bersworth, F. C., and Martell, A. E., 1949. ]. Org. _ Chem., 14, 355.

[25] Wu, Chin-Yung, and Tsou, Chen-Lu, 1955. Scientia Sinica, 4, 137. .

[26] Levin, R., and Brauer, R. W., 1951. J. Lab. Clin. Med., 38, 474.

[27] Bitcher, Th., 1947. Biochem. Biophys. Acta, 1, 292. [28] Kearney, E. B., Singer, T. P., and Zastrow, N., 1955. Arch. Biochem. Biophys., 55, 579.

[29] Lineweaver, H., and Burk, D., 1934. J. Amer. Chem. Soc., 56, 658.

[30] Thorn, M. B., 1953. Biochem. J., 54, 540.

[31] Bessey, O. A., Lowry, O. H., and Love, R. H., 1949. J. Biol, Chem. 180, 755. [32] Warburg, O., and Christian, W., 1938. Biochem. Z., 298, 150.

[33] Weber, G., 1950. Biochem. J., 47, 114.