Abstract
The [Ca2+ + Mg2+]-ATPase activity of bovine lactating mammary gland is associated with membranes. This study compares the ATPase activity in microsomal membranes to that of the Golgi apparatus. The enzyme activity in both fractions hydrolyzed Ca(2+)-ATP and Mg(2+)-ATP. The ATPase activities were inhibited by p-chloromercuribenzoate, indicating the involvement of a sulfhydryl group for activity. Although calmodulin had no effect on the ATPase activities of the two fractions, calmodulin antagonists (chlorpromazine, fluphenazine, and trifluoperazine) were inhibitory. Strong inhibitors of the ATPase activities were vanadate, dicyclohexyl-carbodiimide, La3+, and Zn2+. There were some differences in the activities from two membrane fractions. Although both fractions could hydrolyze all of the triphosphonucleotides, cytidine-5'-triphosphate and uridine-5'-triphosphate were poor substrates for the Golgi enzyme. Detergents diminished the activity of the microsomal enzyme to a much greater extent than the ATPase of the Golgi apparatus. Thus, the intact membrane may be more critical to microsomal activity. The role of these enzymes in Ca2+ accumulation in milk is discussed.
References
Feb 1, 1975·Experimental Cell Research·C R Baumrucker, T W Keenan
Jun 1, 1978·Journal of Ultrastructure Research·F B Wooding, G Morgan
Feb 11, 1992·Archives of Biochemistry and Biophysics·H M FarrellE D Wickham
Sep 1, 1986·Analytical Biochemistry·K M ChanK D Junger
Mar 15, 1985·The Biochemical Journal·S S VirkS B Shears
Jun 20, 1972·Biochemistry·E W BinghamR J Carroll
Jun 29, 1971·Biochimica Et Biophysica Acta·A Z Budzynski, G E Means
Mar 18, 1969·Biochimica Et Biophysica Acta·R D Palmiter
Jan 1, 1982·Annals of the New York Academy of Sciences·J M McDonaldH A Pershadsingh
Jan 1, 1984·Comparative Biochemistry and Physiology. A, Comparative Physiology·C Holt, R Jenness
Nov 15, 1984·The Biochemical Journal·C D Watters
Apr 3, 1982·Biochimica Et Biophysica Acta·E S Szymanski, H M Farrell
Apr 3, 1981·Biochimica Et Biophysica Acta·D W West
Sep 1, 1961·The Biochemical Journal·R J PENNINGTON
Citations
Nov 14, 2007·Journal of Mammary Gland Biology and Neoplasia·Joshua N VanHouten, John J Wysolmerski
Jul 19, 2005·Journal of Mammary Gland Biology and Neoplasia·Margaret C Neville
Sep 12, 2003·American Journal of Physiology. Cell Physiology·Timothy A ReinhardtW Ray Waters
May 7, 2008·Cellular & Molecular Biology Letters·David B Shennan
Oct 13, 2000·American Journal of Physiology. Cell Physiology·T A ReinhardtR L Horst
Apr 13, 1999·The American Journal of Physiology·T A Reinhardt, R L Horst