Three new potential cAMP affinity labels. Inactivation of human platelet low Km cAMP phosphodiesterase by 8-[(4-bromo-2,3-dioxobutyl)thio]adenosine 3',5'-cyclic monophosphate. 1990

P G Grant, and D L DeCamp, and J M Bailey, and R W Colman, and R F Colman
Temple University School of Medicine, Philadelphia, Pennsylvania 19140.

Three new analogues of cAMP have been synthesized and characterized: 2-[(4-bromo-2,3-dioxobutyl)thio]adenosine 3',5'-cyclic monophosphate (2-BDB-TcAMP), 2-[(3-bromo-2-oxopropyl)thio]-adenosine 3',5'-cyclic monophosphate (2-BOP-tcAMP), and 8-[(4-bromo-2,3-dioxobutyl)thio]adenosine 3',5'-cyclic monophosphate (8-BDB-TcAMP). The bromoketo moiety has the ability to react with the nucleophilic side chains of several amino acids, while the dioxobutyl group can interact with arginine. These cAMP analogues were tested for their ability to inactivate the low Km (high affinity) cAMP phosphodiesterase from human platelets. The 2-BDB-TcAMP and 2-BOP-TcAMP were competitive inhibitors of cAMP hydrolysis by the phosphodiesterase with Ki values of 0.96 +/- 0.12 and 0.70 +/- 0.12 microM, respectively. However, 2-BDB-TcAMP and 2-BOP-TcAMP did not irreversibly inactivate the phosphodiesterase at pH values from 6.0 to 7.5 and at concentrations up to 10 mM. These results indicate that although the 2-substituted TcAMP analogues bind to the enzyme, there are no reactive amino acids in the vicinity of the 2-position of the cAMP binding site. In contrast, incubation of the platelet low Km cAMP phosphodiesterase with 8-BDB-TcAMP resulted in a time-dependent, irreversible inactivation of the enzyme with a second-order rate constant of 0.031 +/- 0.009 min-1 mM1. Addition of the substrates, cAMP and cGMP, and the product, AMP, to the reaction mixture resulted in marked decreases in the inactivation rate, suggesting that the inactivation was due to reaction at the active site of the phosphodiesterase.(ABSTRACT TRUNCATED AT 250 WORDS)

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
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
D002621 Chemistry A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
D004789 Enzyme Activation Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme. Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D005069 Evaluation Studies as Topic Works about studies that determine the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. Critique,Evaluation Indexes,Evaluation Methodology,Evaluation Report,Evaluation Research,Methodology, Evaluation,Pre-Post Tests,Qualitative Evaluation,Quantitative Evaluation,Theoretical Effectiveness,Use-Effectiveness,Critiques,Effectiveness, Theoretical,Evaluation Methodologies,Evaluation Reports,Evaluation, Qualitative,Evaluation, Quantitative,Evaluations, Qualitative,Evaluations, Quantitative,Indexes, Evaluation,Methodologies, Evaluation,Pre Post Tests,Pre-Post Test,Qualitative Evaluations,Quantitative Evaluations,Report, Evaluation,Reports, Evaluation,Research, Evaluation,Test, Pre-Post,Tests, Pre-Post,Use Effectiveness
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000242 Cyclic AMP An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH. Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D000345 Affinity Labels Analogs of those substrates or compounds which bind naturally at the active sites of proteins, enzymes, antibodies, steroids, or physiological receptors. These analogs form a stable covalent bond at the binding site, thereby acting as inhibitors of the proteins or steroids. Affinity Labeling Reagents,Labeling Reagents, Affinity,Labels, Affinity,Reagents, Affinity Labeling
D001665 Binding Sites The parts of a macromolecule that directly participate in its specific combination with another molecule. Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D013873 Thionucleotides Nucleotides in which the base moiety is substituted with one or more sulfur atoms.

Related Publications

P G Grant, and D L DeCamp, and J M Bailey, and R W Colman, and R F Colman
June 2000, Thrombosis research,
P G Grant, and D L DeCamp, and J M Bailey, and R W Colman, and R F Colman
October 1988, Biochemistry,
P G Grant, and D L DeCamp, and J M Bailey, and R W Colman, and R F Colman
July 1990, Biochemistry,
P G Grant, and D L DeCamp, and J M Bailey, and R W Colman, and R F Colman
December 1985, Biochemistry,
P G Grant, and D L DeCamp, and J M Bailey, and R W Colman, and R F Colman
March 1990, Biochemistry,
Copied contents to your clipboard!