The relevance of K i calculation for bi-substrate enzymes illustrated by kinetic evaluation of a novel lysine (K) acetyltransferase 8 inhibitor
摘要:
Histone acetyltransferases (HATs) are important mediators of epigenetic post-translational modifications of histones that play important roles in health and disease. A disturbance of these modifications can result in disease states, such as cancer or inflammatory diseases. Inhibitors of HATs (HATi) such as lysine (K) acetyltransferase 8 (KAT8), could be used to study the epigenetic processes in diseases related to these enzymes or to investigate HATs as therapeutic targets. However, the development of HATi is challenged by the difficulties in kinetic characterization of HAT enzymes and their inhibitors to enable calculation of a reproducible inhibitory potency. In this study, a fragment screening approach was used, enabling identification of 4-amino-1-naphthol, which potently inhibited KAT8. The inhibitor was investigated for enzyme inhibition using kinetic and calorimetric binding studies. This allowed for calculation of the K-i values for both the free enzyme as well as the acetylated intermediate. Importantly, it revealed a striking difference in binding affinity between the acetylated enzyme and the free enzyme, which could not be revealed by the IC50 value. This shows that kinetic characterization of inhibitors and calculation of K-i values is crucial for determining the binding constants of HAT inhibitors. We anticipate that more comprehensive characterization of enzyme inhibition, as described here, is needed to advance the field of HAT inhibitors. (C) 2017 Elsevier Masson SAS. All rights reserved.
Substituted guanidines and derivatives thereof as modulators of
申请人:Cambridge NeuroScience, Inc.
公开号:US05403861A1
公开(公告)日:1995-04-04
Modulators of neurotransmitter release including substituted guanidines, N"-aminoguanidines, and N,N'N",N"'-tetrasubstituted hydrazinedicarboximidamides, and pharmaceutical compositions thereof are disclosed. Also disclosed are methods involving the use of such neurotransmitter release modulators for the treatment or prevention of pathophysiologic conditions characterized by the release of excessive or inappropriate levels of neurotransmitters. Also disclosed are screening assays for compounds which selectively inhibit glutamate release. Also disclosed are methods of blocking voltage sensitive sodium and calcium channels in mammalian nerve cells.
Photochemical generation and lifetimes in water of p-aryloxy- and p-alkoxyphenylnitrenium ions
作者:Pratima Ramlall、Robert A. McClelland
DOI:10.1039/a807567k
日期:——
the para position leads through a hemiacetal (or halohydrin) to the quinone imine, whose hydrolysis results in the final quinone product. Three kinetic processes are observed, the nitrenium hydration on the µs time scale, the hemiacetalbreakdown on the ms time scale, and the imine hydrolysis on the minutes time scale. The nitrenium ions have lifetimes in aqueous solution of 50 ns (4-PhO), 70 ns (4-MeOC6H4O)
本文描述了以下4X-C的水溶液照射产品和闪光光解的研究6 ħ 4 Ñ 3 [X =的MeO(12A),环氧乙烷(12B),镨我O(图12C),卜吨O(12D),C 6 H 5 O(12e),4-MeOC 6 H 4 O(12f),F,Cl]和4-甲氧基-1-萘叠氮化物(15)。p苯醌(或1,4-萘),观察到作为产品,与图12a-d,15%,40%与12E,26%,4-F,用4-氯15%的70-90%的产率。醌是通过一种途径产生的,通过溶剂水分子的质子化作用,将最初形成的单线态芳基亚硝烯淬灭,形成亚硝酸根离子。该阳离子在水合处的水合对位通过半缩醛(或卤代醇)到达醌亚胺,后者水解产生最终的醌产物。观察到三个动力学过程,即在µs时间尺度上的nitr水合,在ms时间尺度上的半缩醛分解以及在分钟时间尺度上的亚胺水解。硝酸根离子在水溶液中的寿命为50 ns(4-PhO),70 ns(4-MeOC 6 H
Studies in the Naphthalene Series. I. Oxidative Coupling of 1-Naphthol
作者:J. D. Edwards、J. L. Cashaw
DOI:10.1021/ja01652a082
日期:1954.12
SUBSTITUTED GUANIDINES AND DERIVATIVES THEREOF AS MODULATORS OF NEUROTRANSMITTER RELEASE AND NOVEL METHODOLOGY FOR IDENTIFYING NEUROTRANSMITTER RELEASE BLOCKERS