Biomaterial Database

Activation of cardiac adenylate cyclase: horminal modification of the magnesium ion requirement. 1977

R Alvarez, and J J Bruno

Histamine and epinephrine stimulate the activity of guinea pig heart adenylate cyclase [ATP pyrophosphate-lyase (cyclizing) EC 4.6.1.1], in part, by decreasing the requirement for Mg2+ as an activator. This effect may represent an increase in affinity for Mg2+ and/or a decrease in sensitivity of the enzyme towards inhibition by free ATP. Both of these inotropic hormones also increase maximum velocity. Pretreatment of the membrane-bound enzyme with EDTA, to remove available divalent cations, almost eliminates persistent stimulation by guanyl-5'-yl imidodiphosphate [Gpp(NH)p]. Addition of Mg2+ to the preincubation medium restores the capacity of Gpp(NH)p to acutely activate the enzyme. These results indicate that Mg2+ interacts with the nucleotide (GTP) regulatory site. Persistent stimulation of the enzyme by either Gpp(NH)p or fluoride ion also involves a decrease in the requirement for Mg2+ and an increase in maximum velocity.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
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
D004837	Epinephrine	The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.	Adrenaline,4-(1-Hydroxy-2-(methylamino)ethyl)-1,2-benzenediol,Adrenaline Acid Tartrate,Adrenaline Bitartrate,Adrenaline Hydrochloride,Epifrin,Epinephrine Acetate,Epinephrine Bitartrate,Epinephrine Hydrochloride,Epinephrine Hydrogen Tartrate,Epitrate,Lyophrin,Medihaler-Epi,Acetate, Epinephrine
D006150	Guanine Nucleotides		Guanine Nucleotide,Guanosine Phosphates,Nucleotide, Guanine,Nucleotides, Guanine,Phosphates, Guanosine
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D006632	Histamine	An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.	Ceplene,Histamine Dihydrochloride,Histamine Hydrochloride,Peremin
D000067956	Adenylyl Cyclase Inhibitors	Compounds that bind to and inhibit the action of ADENYLYL CYCLASES.	Adenylate Cyclase Inhibitors,Cyclase Inhibitors, Adenylate,Cyclase Inhibitors, Adenylyl,Inhibitors, Adenylate Cyclase,Inhibitors, Adenylyl Cyclase
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