Biomaterial Database

Effect of adenine nucleotides on cyclooxygenase and lipoxygenase enzyme products of arachidonic acid in human platelets. 1990

Y P Dragan, and E F Ellis

Department of Pharmacology and Toxicology, Medical College of Virginia, Richmond 23298.

Nucleotides are known to enhance cyclooxygenase product formation in several tissues and, in addition, are believed to function as cofactors for mammalian 5-lipoxygenases. Since nucleotides are released by stimulated platelets and by damaged tissue, we examined the hypothesis that nucleotides can affect the metabolism of arachidonic acid (AA) in washed human platelets. The various nucleotides were given 15 sec prior to the addition of 3 microM arachidonic acid and 1 muCi [3H]AA. We found that the phosphorylated adenine derivatives (ATP, ADP, and AMP) increased the formation of 12-hydroxyeicosatetraenoic acid (12-HETE) by 2-fold without altering the formation of cyclooxygenase products. Adenosine was without effect on 12-HETE formation. ATP also stimulated 12-HETE formation in lysed platelets. This suggests that the 12-lipoxygenase enzyme of platelets can be regulated by adenine nucleotides. We next determined the portion of the nucleotide molecule responsible for the enhanced 12-lipoxygenase activity of platelets. Alteration of the nucleotide base led to a decrease in stimulation, with GTP less active than ATP, and UTP even less active than GTP. Studies with adenine nucleotides showed that the length of the phosphate chain was not important. We also found that the stable methylene isosters of ATP (alpha, beta-methylene ATP and beta, gamma-methylene ATP) increased 12-HETE formation, suggesting that the conformation and hydrolysis of the phosphate chain are not responsible for the stimulatory activity. Cyclic 3',5'AMP and 3'AMP were inactive, implying the necessity for a free phosphate at the 5' position for nucleotide stimulation of 12-HETE synthesis. In conclusion, platelet 12-lipoxygenase was stimulated by ATP, as is true for several mammalian 5-lipoxygenases. However, cyclooxygenase product formation by platelets was not altered by nucleotide addition. These studies suggest that following in vivo injury or platelet aggregation, when local concentrations of nucleotides are high, platelet lipoxygenase activity may be stimulated.

UI	MeSH Term	Description	Entries
D011451	Prostaglandin-Endoperoxide Synthases	Enzyme complexes that catalyze the formation of PROSTAGLANDINS from the appropriate unsaturated FATTY ACIDS, molecular OXYGEN, and a reduced acceptor.	Fatty Acid Cyclo-Oxygenase,PGH Synthase,Prostaglandin H Synthase,Prostaglandin Synthase,Prostaglandin-Endoperoxide Synthase,Arachidonic Acid Cyclooxygenase,Cyclo-Oxygenase,Cyclooxygenase,Cyclooxygenases,Hydroperoxide Cyclase,PGH2 Synthetase,Prostaglandin Cyclo-Oxygenase,Prostaglandin Cyclooxygenase,Prostaglandin Endoperoxide Synthetase,Prostaglandin G-H Synthase,Prostaglandin H2 Synthetase,Prostaglandin Synthetase,Cyclase, Hydroperoxide,Cyclo Oxygenase,Cyclo-Oxygenase, Fatty Acid,Cyclo-Oxygenase, Prostaglandin,Cyclooxygenase, Arachidonic Acid,Cyclooxygenase, Prostaglandin,Endoperoxide Synthetase, Prostaglandin,Fatty Acid Cyclo Oxygenase,G-H Synthase, Prostaglandin,Prostaglandin Cyclo Oxygenase,Prostaglandin Endoperoxide Synthases,Prostaglandin G H Synthase,Synthase, PGH,Synthase, Prostaglandin,Synthase, Prostaglandin G-H,Synthase, Prostaglandin H,Synthase, Prostaglandin-Endoperoxide,Synthases, Prostaglandin-Endoperoxide,Synthetase, PGH2,Synthetase, Prostaglandin,Synthetase, Prostaglandin Endoperoxide,Synthetase, Prostaglandin H2
D001792	Blood Platelets	Non-nucleated disk-shaped cells formed in the megakaryocyte and found in the blood of all mammals. They are mainly involved in blood coagulation.	Platelets,Thrombocytes,Blood Platelet,Platelet,Platelet, Blood,Platelets, Blood,Thrombocyte
D006160	Guanosine Triphosphate	Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.	GTP,Triphosphate, Guanosine
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006893	Hydroxyeicosatetraenoic Acids	Eicosatetraenoic acids substituted in any position by one or more hydroxy groups. They are important intermediates in a series of biosynthetic processes leading from arachidonic acid to a number of biologically active compounds such as prostaglandins, thromboxanes, and leukotrienes.	HETE,Acids, Hydroxyeicosatetraenoic
D000227	Adenine Nucleotides		Adenine Nucleotide,Adenosine Phosphate,Adenosine Phosphates,Nucleotide, Adenine,Nucleotides, Adenine,Phosphate, Adenosine,Phosphates, Adenosine
D000244	Adenosine Diphosphate	Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.	ADP,Adenosine Pyrophosphate,Magnesium ADP,MgADP,Adenosine 5'-Pyrophosphate,5'-Pyrophosphate, Adenosine,ADP, Magnesium,Adenosine 5' Pyrophosphate,Diphosphate, Adenosine,Pyrophosphate, Adenosine
D000249	Adenosine Monophosphate	Adenine nucleotide containing one phosphate group esterified to the sugar moiety in the 2'-, 3'-, or 5'-position.	AMP,Adenylic Acid,2'-AMP,2'-Adenosine Monophosphate,2'-Adenylic Acid,5'-Adenylic Acid,Adenosine 2'-Phosphate,Adenosine 3'-Phosphate,Adenosine 5'-Phosphate,Adenosine Phosphate Dipotassium,Adenosine Phosphate Disodium,Phosphaden,2' Adenosine Monophosphate,2' Adenylic Acid,5' Adenylic Acid,5'-Phosphate, Adenosine,Acid, 2'-Adenylic,Acid, 5'-Adenylic,Adenosine 2' Phosphate,Adenosine 3' Phosphate,Adenosine 5' Phosphate,Dipotassium, Adenosine Phosphate,Disodium, Adenosine Phosphate,Monophosphate, 2'-Adenosine,Phosphate Dipotassium, Adenosine,Phosphate Disodium, Adenosine
D000255	Adenosine Triphosphate	An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.	ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults