Do Electrostatic Interactions with Positively Charged Active Site Groups Tighten the Transition State for Enzymatic Phosphoryl Transfer?
摘要:
The effect of electrostatic interactions on the transition-state character for enzymatic phosphoryl transfer has been a subject of much debate. In this work, we investigate the transition state for alkaline phosphatase (AP) using linear free-energy relationships (LIFERs). We determined k(cat)/K-M for a series of aryl sulfate ester monoanions to obtain the Bronsted coefficient, beta(lg)., and compared the value to that obtained previously for a series of aryl phosphorothioate ester dianion substrates. Despite the difference in substrate charge, the observed Bronsted coefficients for AP-catalyzed aryl sulfate and aryl phosphorothioate hydrolysis (-0.76 +/- 0.14 and -0.77 +/- 0.10, respectively) are strikingly similar, with steric effects being responsible for the uncertainties in these values. Aryl sulfates and aryl phosphates react via similar loose transition states in solution. These observations suggest an apparent equivalency of the transition states for phosphorothioate and sulfate hydrolysis reactions at the AP active site and, thus, negligible effects of active site electrostatic interactions on charge distribution in the transition state.
Sulfonation and sulfation in reactions of <i>C</i>
-methylated phenols and anisoles with sulfur trioxide. 4-Substituted phenyl hydrogen sulfates: Effective reagents for transsulfonation
作者:Hans D. Goossens、Hans J. A. Lambrechts、Hans Cerfontain、Peter de Wit
DOI:10.1002/recl.19881070606
日期:——
The sulfation and sulfonation of the methyl- and dimethylphenols with 0.9 and 4.0 equiv. of SO3 in nitromethane at 0°C have been studied. On using 0.9 equiv. of SO3, the sulfonic acid product distributions are determined by the ortho- and para-directing effect of the activating hydroxy substituent. In the reactions with 4.0 equiv. of SO3, the sulfonic acid product distributions are affected by the
COMPOSITIONS AND METHODS FOR TREATING ESTROGEN-RELATED MEDICAL DISORDERS
申请人:THE BOARD OF TRUSTEES OF THE UNIVERSITY OF ILLINOIS
公开号:US20150291552A1
公开(公告)日:2015-10-15
Disclosed herein are methods for treatment of estrogen-related medical disorders. The methods of treatment may comprise administering to a subject in need of such treatment a composition comprising a therapeutically effective amount of at least one compound of formula (I) or a pharmaceutically acceptable salt thereof.
SET OF BIOMARKERS FOR THE DIAGNOSIS OF BRUGADA SYNDROME
申请人:Cardiomix S.r.l.
公开号:EP3865591A1
公开(公告)日:2021-08-18
The present invention relates to a specific set of circulating biomarkers and related methods and kits for the diagnosis of Brugada Syndrome in a human being.