1. At short incubation times, and under suitable osmotic conditions, the lactose synthesized by Golgi-derived vesicles of rat mammary gland is 85-90% particulate. Evidence is presented for its occlusion within the lumen ofthe vesicles. 2. Ovalbumin is used as a bulky active-site inhibitor to show that the active site of lactose synthase lies on the inner face of the Golgi membrane. 3. Phlorrhizin and phloretin inhibit lactose synthesis by such vesicles, indicating the presence of a glucose-transport system. 4. The relationship of this topography to the synthesis of N-acetylneuraminyl-lactose and to the secretion of milk sugars is discussed.
Similar content being viewed by others
References
Ashwell, G. (1966) Methods Enzymol. 8, 85-95
Barra, H. S., Cumar, F. A. & Caputto, R. (1969) J. Biol. Chem. 244, 6233-6240
Brew, K. (1969) Nature (London) 223, 671-672
Brew, K., Vanaman, T. C. & Hill. R. L. (1968) Proc. Nat. Acad. Sci. U.S. 59, 491-497
Brodbeck, U. & Ebner, K. E. (1966) J. Biol. Chem. 241, 5526-5532
Carlson, D. M., Jourdian, G. W. & Roseman, S. (1973) J. Biol. Chem. 248, 5742-5750
Coffey, R. G. & Reithel, F. J. (1968) Biochem. J. 109, 177-183
Dallner, G. & Ernster, L. (1968) J. Histochem. Cytochem. 16, 611-632
Ehrenreich, J. H., Bergeron, J. J. M., Siekevitz, P. &Palade, G. E. (1973) J. Cell Biol. 59, 45-72
Gumaa, K. A., Greenbaum, A. L. & McLean, P. (1971) in Lactation (Falconer, I. R., ed.), pp. 197-238, Butterworths, London
Hollman, K. H. (1968) Z. Zellforsch. Mikrosk. Anat. 87, 266-277
Jones, E. A. (1972) Biochem. J. 126, 67-78
Keenan, T. W., Huang, C. M. & Morré, D. J. (1972a) J. Dairy Sci. 55, 51-57
Keenan, T. W., Huang, C. M. & Morré, D. J. (1972b) J. Dairy Sci. 55, 1577-1585
Kuhn, N. J. (1968) Biochem. J. 106, 743-748
Kuhn, N. J. (1969) J. Endocrinol. 44, 39-54
Kuhn, N. J. (1971) in Lactation (Falconer, I. R., ed.), pp. 161-176, Butterworths, London
Kuhn, N. J. (1972) Biochem. J. 130, 177-180
Montgomery, R., Lee, Y. C. & Wu, Y. C. (1965) Biochemistry 4, 566-577
Morrison, J. F. & Ebner, K. E. (1971a) J. Biol. Chem. 246, 3977-3984
Morrison, J. F. & Ebner, K. E. (1971b) J. Biol. Chem. 246, 3985-3991
Morrison, J. F. & Ebner, K. E. (1971c) J. Biol. Chem. 246, 3992-3998
Murphy, G., Ariyanayagam, A. D. & Kuhn, N. J. (1973) Biochem. J. 136, 1105-1116
Palmiter, R. D. (1969) Nature (London) 221, 912-914
Redman, C. M., Siekevitz, P. & Palade, G. E. (1966) J. Biol. Chem. 241, 1150-1158
Reithel, F. J. (1963) in Methods of Enzymatic Analysis (Bergmeyer, H. U., ed.), p. 103, Academic Press, New York and London
Schanbacher, F. L. & Ebner, K. E. (1970) J. Biol. Chem. 245, 5057-5061
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kuhn, N.J., White, A. The Topography of Lactose Synthesis. J Mammary Gland Biol Neoplasia 14, 213–220 (2009). https://doi.org/10.1007/s10911-009-9136-6
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10911-009-9136-6