Ammonium ions enhance proteolytic activation of adenylate cyclase and decrease its sensitivity to inhibition by “P”-site agonists was written by Yeung, Siu Mei Helena;Shoshani, Ilana;Stuebner, Dorothee;Johnson, Roger A.. And the article was included in Archives of Biochemistry and Biophysics in 1989.COA of Formula: C10H13N5O2 This article mentions the following:
A detergent-dispersed adenylate cyclase from rat brain was used to study the effects of ammonium salts and polyamines on the proteolytic activation of the enzyme by a sperm protease and on the sensitivity of adenylate cyclase to inhibition via its P-site. A purified preparation of a trypsinlike serine protease from bovine sperm was used to activate solubilized adenylate cyclase in the presence of guanosine 5′-O-(3-thiotriphosphate (GTPγS). The proteolytically activated form of adenylate cyclase was particularly sensitive to further activation by NH4HCO3. The activation by NH4HCO3 was due to the NH4+ cation and was characterized by an increased Vmax and by a decreased sensitivity of adenylate cyclase to inactivation by elevated concentrations of the sperm protease or by trypsin. NH4Cl and (NH4)2SO4 also caused biphasic effects on adenylate cyclase, that mimicked but were less effective than those caused by NH4HCO3. Consistent with observations of others, adenylate cyclase activity was enhanced by NH+ whether in the presence of reversible (Mn2+) or irreversible (GTPγS) activators. Mn2+– and GTPγS-stimulated activities were similarly optimally enhanced by 30 mM (NH4)2SO4 and by 30-150 mM NH4Cl or NH4HCO3. NH4+ did not increase the activity of the purified catalytic unit. Moreover, the effect of NH4+ was not accompanied by an increased rate of activation by GTPγS, suggesting that the activation of Gs (guanine nucleotide-dependent stimulatory component) may not be the primary cause of stimulation by ammonium salts. Several polyamines at millimolar concentrations blocked the stimulatory effect of NH4+. This was observed when adenylate cyclase was activated by Mn2+, but not when it was activated by GTPγS or by the sperm protease plus GTPγS. The inhibitory effect of polyamines was not due to the formation of a complex with ATP. Both the increase in Vmax of the Mn2+-stimulated enzyme by NH4+ and the decrease in Vmax caused by spermine were accompanied by an increase in the apparent Km for MnATP. Spermine increased the IC50 for inhibition of Mn2+-activated adenylate cyclase by 2′,5′-dideoxyadenosine (2′,5′-ddAdo) from 0.75 to 4.6 μM, consistent with the idea that increased sensitivity of P-site-mediated inhibition is associated with increased enzyme activity. In contrast, activation of Mn2+-stimulated adenylate cyclase by 30 mM (NH4)2SO4 also reduced sensitivity to inhibition by 2′,5′-ddAdo (IC50 1.1 μM). This decreased sensitivity to inhibition by 2′,5′-ddAdo induced by NH4+ was also observed on GTPS-activated or proteolytically activated adenylate cyclase. Thus, activation of adenylate cyclase by ammonium salts may be due to an effect on the conformation and(or) stability of the active form of the enzyme, leading to increased enzyme activity as well as to decreased proteolytic inactivation. In the experiment, the researchers used many compounds, for example, (2R,3S,5R)-5-(6-Amino-9H-purin-9-yl)-2-methyltetrahydrofuran-3-ol (cas: 6698-26-6COA of Formula: C10H13N5O2).
(2R,3S,5R)-5-(6-Amino-9H-purin-9-yl)-2-methyltetrahydrofuran-3-ol (cas: 6698-26-6) belongs to tetrahydrofuran derivatives. Tetrahydrofuran (THF), or oxolane, is mainly used as a precursor to polymers. Being polar and having a wide liquid range, THF is a versatile solvent. It is more basic than diethyl ether and forms stronger complexes with Li+, Mg2+, and boranes. It is a popular solvent for hydroboration reactions and for organometallic compounds such as organolithium and Grignard reagents.COA of Formula: C10H13N5O2
Referemce:
Tetrahydrofuran – Wikipedia,
Tetrahydrofuran | (CH2)3CH2O – PubChem