scholarly journals Identical subcellular distribution of palmitoyl-CoA and arachidonoyl-CoA synthetase activities in human blood platelets

1989 ◽  
Vol 261 (1) ◽  
pp. 71-76 ◽  
Author(s):  
A M Bakken ◽  
M Farstad
Keyword(s):  
Enzyme Activity ◽  
Arachidonic Acid ◽  
Human Blood ◽  
Blood Platelets ◽  
The Other ◽  
Heat Inactivation ◽  
Tubular System ◽  
Chain Acyl ◽  
Human Blood Platelets ◽  
Long Chain

Fractionation of human blood platelets showed that palmitoyl-CoA synthetase and arachidonoyl-CoA synthetase activities had an identical distribution among subcellular fractions. The activity was highest with arachidonic acid as substrate in all fractions, with an enzyme activity of 50 nmol/min per mg of protein, in a ‘dense-tubular-system’-enriched fraction. The ratio activities with arachidonate and palmitate as substrates was about 1.5 in all fractions. Heat inactivation did not distinguish between arachidonoyl-CoA synthetase and a palmitoyl-CoA synthetase. On the other hand, heat inactivation indicated two pools of long-chain acyl-CoA synthetases: one in a mitochondria- and one in the dense-tubular-system-enriched fraction.

The content of coenzyme A, acetyl-CoA and long-chain acyl-CoA in human blood platelets

1982 ◽  
Vol 126 (3) ◽  
pp. 307-313 ◽  
Author(s):  
Ole C. Ingebretsen ◽  
Anne M. Bakken ◽  
Mikael Farstad
Keyword(s):  
Human Blood ◽  
Coenzyme A ◽  
Blood Platelets ◽  
Acetyl Coa ◽  
Chain Acyl ◽  
Human Blood Platelets ◽  
Long Chain

scholarly journals ULTRASTRUCTURAL LOCALIZATION OF Mg++-DEPENDENT DINITROPHENOL-STIMULATED ADENOSINE TRIPHOSPHATASE IN HUMAN BLOOD PLATELETS

1967 ◽  
Vol 15 (5) ◽  
pp. 267-272 ◽  
Author(s):  
VICTOR G. VETHAMANY ◽  
SYDNEY S. LAZARUS
Keyword(s):  
Enzyme Activity ◽  
Plasma Membrane ◽  
Human Blood ◽  
Adenosine Triphosphatase ◽  
Blood Platelets ◽  
Ultrastructural Localization ◽  
Human Platelets ◽  
Structural Localization ◽  
Adenosine Triphosphatase Activity ◽  
Human Blood Platelets

Fine structural localization of adenosine triphosphatase activity was studied in human platelets briefly fixed in cold formol calcium and then incubated in lead medium with added dinitrophenol. Under these conditions, the Mg++-dependent dinitrophenol-stimulated adenosine triphosphatase of platelet mitochondria was demonstrated, but neither granules nor plasma membrane showed enzyme activity.

scholarly journals Intracellular mechanisms in the activation of human platelets by low-density lipoproteins

1987 ◽  
Vol 242 (2) ◽  
pp. 559-564 ◽  
Author(s):  
H E Andrews ◽  
J W Aitken ◽  
D G Hassall ◽  
V O Skinner ◽  
K R Bruckdorfer
Keyword(s):  
Arachidonic Acid ◽  
Human Blood ◽  
Blood Platelets ◽  
Human Platelets ◽  
Low Density Lipoproteins ◽  
Low Density ◽  
Protein L ◽  
Stimulus Response ◽  
Dense Granules ◽  
Human Blood Platelets

Low-density lipoproteins (LDL) have been shown to cause aggregation of human blood platelets at concentrations above 2 g of protein/l. The secretion of the contents of platelet dense granules was detected, but not that of the lysosomes. LDL gave rise to a mobilization of [3H]arachidonic acid from phospholipids and the appearance of products of the cyclo-oxygenase pathway after only 10 s. LDL-promoted aggregation was inhibited by both aspirin and indomethacin. There was an increase in 3H-labelled diacylglycerols and the phosphorylation of 47 kDa proteins. LDL therefore shares at least some of the mechanisms of stimulus/response coupling with those of other agonists.

scholarly journals The activity and subcellular distribution of the peroxisomal enzyme acyl-CoA oxidase in human blood platelets

1992 ◽  
Vol 286 (3) ◽  
pp. 829-831 ◽  
Author(s):  
M Farstad ◽  
A M Bakken ◽  
R K Berge
Keyword(s):  
Endoplasmic Reticulum ◽  
Human Blood ◽  
Subcellular Distribution ◽  
Blood Platelets ◽  
Peroxisomal Enzyme ◽  
Good Accordance ◽  
Tubular System ◽  
Acyl Coa Oxidase ◽  
Human Blood Platelets

The peroxisomal enzyme acyl-CoA oxidase is localized in the ‘dense-tubular-system-enriched fraction’, probably identical with the endoplasmic reticulum, in human blood platelets. This localization is strongly different from the localization of catalase which seems to be a cytosolic enzyme, in agreement with Marcus, Zucker-Franklin, Safir & Ullman [(1966) J. Clin. Invest. 45, 14-28]. A localization of acyl-CoA oxidase in the endoplasmic reticulum seems to be in good accordance with the important role of peroxisomes in the metabolism of prostaglandins, as recently demonstrated by Diczfalusy, Kase, Alexson & Bjørkhem [(1991) J. Clin. Invest. 88, 978-984].

scholarly journals Cytochemical localization of ouabain-sensitive (K+)-dependent p-nitrophenyl phosphatase (transport ATPase) in human blood platelets.

1980 ◽  
Vol 28 (11) ◽  
pp. 1183-1188 ◽  
Author(s):  
L S Cutler ◽  
M B Feinstein ◽  
C P Christian
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Human Blood ◽  
Human Platelet ◽  
Blood Platelets ◽  
Cytochemical Localization ◽  
Transport Atpase ◽  
Tubular System ◽  
Membrane Compartments ◽  
Human Blood Platelets

The ultrastructural cytochemical localization of a potassium-dependent oubain-sensitive nitrophenyl phosphatase (transport ATPase) activity in human blood platelets is described. This potassium-dependent nitrophenyl phosphatase activity was not affected by 5 mM levamisole, indicating that the reaction product identified was not due to nonspecific alkaline phosphatase activity. The K+-dependent nitrophenyl phosphatase was strictly localized to the platelet plasma membrane, while the open canalicular system and dense tubular system were devoid of reaction product. In contrast, (Ca2+,Mg2+)-activated ATPase activity was predominantly localized in the open canalicular system and dense tubular system with very little cytochemical activity expressed at the plasma membrane. These data demonstrate a relative segregation of these enzymes into unique membrane compartments of the human platelet. Such data may be useful with regard to identification of purified membrane fractions from platelets and may be significant with regard to the understanding of the function(s) of the different membrane compartments of the human platelet.

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