These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Enzymic hydrolysis of arachidonoyl-phospholipids by rat brain synaptosomes.
    Author: Kelleher JA, Sun GY.
    Journal: Neurochem Int; 1985; 7(5):825-31. PubMed ID: 20492993.
    Abstract:
    Rat brain synaptosomes prelabeled with [(14)C]arachidonoyl-phospholipids were used to study the characteristic properties of acyl hydrolases for different phospholipids. Incubation of the prelabeled synaptosomes at 37 degrees C resulted in a time-dependent decrease of label from phosphatidylcholines (PC) and phosphatidylinositols (PI) and a concomitant increase in label in the free fatty acid fraction, but not diacylglycerols (DG). Phosphatidylserines (PS) also showed a decrease in radioactivity, but little change was observed for phosphatidylethanolamines (PE). At pH 7.4, the release of labeled arachidonate from PI was Ca(2+)-dependent, but that from PS and approx 50% of that from PC was not. The hydrolysis of PC was greatest at pH 7.4, but Ca(2+)-dependent hydrolysis of PI was active from pH 5.5 to 8.5. All detergents tested severely inhibited the release of labeled arachidonate, but in the presence of Ca(2+) and deoxycholate or taurocholate, a large portion of PI was converted to DG through activation of the PI-phosphodiesterase. Different effects on the phospholipid hydrolysis were observed with different phospholipase A(2) inhibitors. Mepacrine (1 mM) inhibited the Ca(2+)-dependent hydrolysis of PI but not PC, whereas dibucaine (1 mM) inhibited PC hydrolysis by 40% but did not affect PI. p-Bromophenacyl bromide (1 mM) dissolved in dimethylsulfoxide (DMSO) only partially inhibited (about 40%) the hydrolysis of PI and PC. The preferential hydrolysis of PI and PC by endogenous phospholipid acyl hydrolase correlates well with the observation that these same two lyso-phospholipids are also preferred by the acyltransferase for the reacylation process.
    [Abstract] [Full Text] [Related] [New Search]