Accession Number : ADA206042


Title :   Phospholipid Requirements of Ca++-Stimulated, Mg++-Dependent ATP hydrolysis in Rat Brain Synaptic Membranes


Descriptive Note : Technical rept. Jun 1984-Dec 1985


Corporate Author : CHEMICAL RESEARCH DEVELOPMENT AND ENGINEERING CENTER ABERDEEN PROVING GROUND MD


Personal Author(s) : Valdes, James J ; Thompson, Roy G ; Ross, David H ; Gandhi, C R


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a206042.pdf


Report Date : Jan 1989


Pagination or Media Count : 24


Abstract : The phospholipid requirement for calcium ion-stimulated, magnesium ion -dependent (ATP) hydrolysis(Ca (++) /Mg (++)-ATPase) and Mg(++) -stimulated ATP hydrolysis (Mg(++)-ATPase) in rat brain synaptosomal membranes was studied employing partial delipidation of the membranes with phospholipase A2 (hog pancreas), phospholipase C (Bacillus Cereus), and phospholipase D (cabbage). Treatment with phospholipase A2 caused an increase in the activities of Ca(++)- ATPase, but Mg(++)-ATPase activity was inhibited. Inhibition of Mg(++) -ATPase activity after phospholipase C treatment was relieved with the addition of phosphatidylinositol-4, 5-biphosphate (PIP2) and to a lesser extent with phosphatidylinositol-4-phosphate (PIP) and phosphatidylcholine (PC). Phosphatidylserine (PS), phosphatidic acid (PA), PIP, and PIP2 brought about the reactivation of Ca(++)/Mg (++) ATPase activity. The Michaelis constants (Kms) for Ca(++) (0.47 micromoles) and Mg(++) (60 micromoles) of the enzyme was unaffected after treatment with the phospholipases.


Descriptors :   *HYDROLYSIS , *PHOSPHOLIPIDS , *ADENOSINE PHOSPHATES , *BRAIN , *MEMBRANES(BIOLOGY) , *SYNAPSE , ENZYMES , VEGETABLES , HYDROLASES , ENZYME INHIBITORS , RATS , CATIONS , CALCIUM , MAGNESIUM , BACILLUS CEREUS , REQUIREMENTS , IONS


Subject Categories : Biochemistry
      Anatomy and Physiology


Distribution Statement : APPROVED FOR PUBLIC RELEASE