86-04-4Relevant articles and documents
Highly regioselective methylation of inosine nucleotide: an efficient synthesis of 7-methylinosine nucleotide
Senthilvelan, Annamalai,Shanmugasundaram, Muthian,Kore, Anilkumar R.
, p. 1011 - 1019 (2020/03/30)
A facile, straightforward, reliable, and an efficient chemical synthesis of inosine nucleotides such as 7-methylinosine 5′-O-monophosphate, 7-methylinosine 5′-O-diphosphate, and 7-methylinosine 5′-O-triphosphate, starting from the corresponding inosine nucleotide is delineated. The present methylation reaction of inosine nucleotide utilizes dimethyl sulfate as a methylating agent and water as a solvent at room temperature. It is noteworthy that the present methylation reaction proceeds smoothly under aqueous conditions that is highly regioselective to afford exclusive 7-methylinosine nucleotide in good yields with high purity (>99.5%).
Dual activity of certain HIT-proteins: A. thaliana Hint4 and C. elegans DcpS act on adenosine 5′-phosphosulfate as hydrolases (forming AMP) and as phosphorylases (forming ADP)
Guranowski, Andrzej,Wojdyla, Anna Maria,Zimny, Jaroslaw,Wypijewska, Anna,Kowalska, Joanna,Jemielity, Jacek,Davis, Richard E.,Bieganowski, Pawel
experimental part, p. 93 - 98 (2010/12/18)
Histidine triad (HIT)-family proteins interact with different mono- and dinucleotides and catalyze their hydrolysis. During a study of the substrate specificity of seven HIT-family proteins, we have shown that each can act as a sulfohydrolase, catalyzing the liberation of AMP from adenosine 5′-phosphosulfate (APS or SO4-pA). However, in the presence of orthophosphate, Arabidopsis thaliana Hint4 and Caenorhabditis elegans DcpS also behaved as APS phosphorylases, forming ADP. Low pH promoted the phosphorolytic and high pH the hydrolytic activities. These proteins, and in particular Hint4, also catalyzed hydrolysis or phosphorolysis of some other adenylyl-derivatives but at lower rates than those for APS cleavage. A mechanism for these activities is proposed and the possible role of some HIT-proteins in APS metabolism is discussed.
Functionally nonequivalent interactions of guanosine 5'-triphosphate, inosine 5'-triphosphate, and xanthosine 5'-triphosphate with the retinal G-protein, transducin, and with G(i)-proteins in HL-60 leukemia cell membranes
Klinker, Jan F.,Seifert, Roland
, p. 551 - 562 (2007/10/03)
G proteins mediate signal transfer from receptors to effector systems. In their guanosine 5'-triphosphate (GTP) bound form, G-protein α-subunits activate effector systems. Termination of G-protein activation is achieved by the high-affinity GTPase [E.C. 3.6.1.-] of their α-subunits. Like GTP, inosine 5' -triphosphate (ITP) and xanthosine 5' triphosphate (XTP) can support effector system activation. We studied the interactions of GTP, ITP, and XTP with the retinal G protein, transducin (TD), and with G-proteins in HL-60 leukemia cell membranes. TD hydrolyzed nucleoside 5'-triphosphates (NTPs) in the order of efficacy GTP > ITP > XTP. NTPs eluted TD from rod outer segment disk membranes in the same order of efficacy. ITP and XTP competitively inhibited TD catalyzed GTP hydrolysis. In HL-60 membranes, the chemoattractants N-formyl-L-methionyl-L-leucyl-L- phenylaline (fMLP) and leukotriene B4 (LTB4,) effectively activated GTP and ITP hydrolysis by G(i) proteins. fMLP and LTB4, were at least l0-fold more potent activators of ITPase than of GTPasc. Complement C5a effectively activated the GTPase of G(i)-proteins but was only a weak stimulator of ITPase. The potency of C5a to activate GTP and ITP hydrolysis was similar. The fMLP stimulated GTPase had a lower K(m) value than the fMLP-stimulated ITPase, whereas the opposite was true for the V(max) values. fMLP, C5a, and LTB4 did not stimulate XTP hydrolysis. Collectively, our data show that GTP, ITP, and XTP bind to G-proteins with different affinities, that G-proteins hydrolyze NTPs with different efficacies, and that chemoattractants stimulate GTP and ITP hydrolysis by G(i)-proteins in a receptor-specific manner. On the basis of our results and the data in the literature, we put forward the hypothesis that GTP, ITP, and XTP act as differential signal amplifiers and signal sorters at the G-protein level.
Nucleoside-Triphosphatase Activity of an ATP-Dependent Enzyme, N-Methylhydantoin Amidohydrolase
Ogawa, Jun,Nirdnoy, Warawadee,Yamada, Hideaki,Shimizu, Sakayu
, p. 1737 - 1739 (2007/10/02)
N-Methylhydantoin amidohydrolase, which catalyzes ATP-dependent hydrolysis of N-methylhydantoin to N-carbamoylsarcosine, was found to hydrolyze several nucleoside triphosphates to nucleoside diphosphates not only in the presence but also in the absence of amide substrates.Amide substrates, such as N-methylhydantoin and dihydrouracil, seem to be absolutely necessary for hydrolysis of ATP and dATP.However, N-methylhydantoin inhibited the hydrolysis of nucleoside triphosphates other than ATP and dATP.The kinetic data suggest that the presence of an amide substrate changes the affinity of the enzyme toward nucleoside triphosphates.
