Preparation and configurational analysis of the stereoisomers of .beta.,.gamma.-bidentate Rh(H2O)4ATP and .alpha.,.beta.,.gamma.-tridentate Rh(H2O)3ATP. A new class of enzyme active site probes

Abstract

The results show that (OP)2Cu+ reacts with 0-hydroxyl radicals to form intermediates with copper-carbon -bonds, which decompose via 0-hydroxyl elimination reactions. It will be very interesting to find out whether (OP)2Cu+ reacts also with free radicals formed in biological systems to produce transients with copper-carbon -bonds. If this is the case, one of the routes for biological damage may occur through such intermediates.Acknowledgment. This study was supported by The Council of Tobacco Research, The Israel Academy of Science, The Israel USA BNF, The Israel Atomic Energy Commission, and the Planning and Granting Committee of the Council of Higher Education. We wish to thank D. Carmi, Y. Nehemia, and Y. Nahon for technical assistance. D.M. wishes to thank I. Evans for her interest and support.

Platinum(II)-Adenosine Phosphothiorate Complexes: Kinetics of Formation and Phosphorus-31 NMR Characterization Studies

“…The complexations of AMP and GMP with Pt(dien)Cl+ follow the familiar two-term rate law (eq 4), consistent with a sequence of reactions shown in eqs 5-7: Pt(dien)Cl+ + H20 -*• Pt(dien)(H20)2+ (5) feet Pt(dien)(H20)2+ + Nu -* Pt(dien)(Nu) (6) *3 Pt(dien)Cl+ + Nu -Pt(dien)(Nu) (7) The value of kB was determined to be (2.0 ± 0.1) X 10-4 s_1 for both the AMP and GMP reactions at 40 °C. This value can be compared with 5 X 10~5 s-1 at 25 °C reported by Belluco et al (26).…”

Investigations of kinase substrate specificity with aqua rhodium(III) complexes of adenosine 5'-triphosphate

“…( 2 )" sample relative to the amount of enzyme present, the Rh(H20)"ATP complex was used in less than a 10:1 ratio to the enzyme. The substrate activities of the Rh(H20)"ATP complexes were measured at pH 6 and at 0 or 25 °C, under which conditions minimal isomerization takes place within the 10-min reaction periods used (Lu et al, 1988) and under which conditions these kinases are known to be active (Dunaway-Mariano & Cleland, 1980b). The substrate activities of the complexes were tested several times with each kinase.…”

“…Rh(III) was chosen because it forms stable aqua complexes, it is diamagnetic, and the aqua RhmATP that it forms exists (Lin et al, 1984), as does Mg11 ATP (Huang & Tsai, 1982;Pecoraro et al, 1984), as an equilibrating mixture of 8,7-bidentate and ,ß,ytridentate isomers. Moreover, unlike the rapid equilibration which occurs among the Mg11 ATP isomers (Pecoraro et al, 1984), we found the isomerization of the RhmATP isomers to be slow enough to allow the individual isomers to be isolated and utilized as enzyme active site probes (Lu et al, 1988). In this paper we report on the binding affinities and substrate activities of the bidentate and tridentate isomers of RhniATP toward selected members of the kinase family of enzymes and on how these affinities and activities compare with those observed previously with the CoinATP and CrmATP complexes.…”

“…General Procedures, a,ß, -Tridentate CofNHsLATP (Cornelius et al, 1977) and ¿.y-bidentate Cr(H20)4ATP (Dunaway-Mariano & Cleland, 1980a) were prepared according to published procedures. Pure isomers of /S.y-bidentate Rh(H20)4ATP and ,/ , -tridentate Rhf^OLATP were prepared by using the method of Lu et al (1988). Prior to use, the HPLC-purified Rh(H20)4ATP and Rhil^OLATP stereoisomers were "desalted" by passing them individually through (0.6 X 20 cm) Sephadex G-10 columns (4 °C, deionized water as eluant).…”

Use of Viscogens, dNTPαS, and Rhodium(III) as Probes in Stopped-Flow Experiments To Obtain New Evidence for the Mechanism of Catalysis by DNA Polymerase β,

“…Synthesis of Rh(III)dNTP Phosphate Complex and Precomplex. Previously, Rh(III)ATP was synthesized and well characterized (24). In this complex Rh(III) coordinates with the phosphate moiety and is called the "phosphate complex" in this paper, to be differentiated from the newly identified "precomplex".…”