Structural analysis of the inhibition of thermolysin by an active-site-directed irreversible inhibitor

Biochemistry ◽  
1983 ◽  
Vol 22 (1) ◽  
pp. 236-240 ◽  
Author(s):  
M. A. Holmes ◽  
D. E. Tronrud ◽  
B. W. Matthews
Keyword(s):  
Structural Analysis ◽  
Active Site ◽  
Irreversible Inhibitor

Effects of viscosity and osmotic stress on the reaction of human butyrylcholinesterase with cresyl saligenin phosphate, a toxicant related to aerotoxic syndrome: kinetic and molecular dynamics studies

2013 ◽  
Vol 454 (3) ◽  
pp. 387-399 ◽  
Author(s):  
Patrick Masson ◽  
Sofya Lushchekina ◽  
Lawrence M. Schopfer ◽  
Oksana Lockridge
Keyword(s):  
Osmotic Stress ◽  
Osmotic Pressure ◽  
Active Site ◽  
Md Simulations ◽  
Catalytic Triad ◽  
Wild Type ◽  
Irreversible Inhibitor ◽  
Enzyme Active Site ◽  
Diffusion Controlled ◽  
Peripheral Site

CSP (cresyl saligenin phosphate) is an irreversible inhibitor of human BChE (butyrylcholinesterase) that has been involved in the aerotoxic syndrome. Inhibition under pseudo-first-order conditions is biphasic, reflecting a slow equilibrium between two enzyme states E and E′. The elementary constants for CSP inhibition of wild-type BChE and D70G mutant were determined by studying the dependence of inhibition kinetics on viscosity and osmotic pressure. Glycerol and sucrose were used as viscosogens. Phosphorylation by CSP is sensitive to viscosity and is thus strongly diffusion-controlled (kon≈108 M−1·min−1). Bimolecular rate constants (ki) are about equal to kon values, making CSP one of the fastest inhibitors of BChE. Sucrose caused osmotic stress because it is excluded from the active-site gorge. This depleted the active-site gorge of water. Osmotic activation volumes, determined from the dependence of ki on osmotic pressure, showed that water in the gorge of the D70G mutant is more easily depleted than that in wild-type BChE. This demonstrates the importance of the peripheral site residue Asp70 in controlling the active-site gorge hydration. MD simulations provided new evidence for differences in the motion of water within the gorge of wild-type and D70G enzymes. The effect of viscosogens/osmolytes provided information on the slow equilibrium E⇌E′, indicating that alteration in hydration of a key catalytic residue shifts the equilibrium towards E′. MD simulations showed that glycerol molecules that substitute for water molecules in the enzyme active-site gorge induce a conformational change in the catalytic triad residue His438, leading to the less reactive form E′.

Kinetic and Structural Analysis of Active Site Mutants of Monofunctional NAD-Dependent 5,10-Methylenetetrahydrofolate Dehydrogenase fromSaccharomyces cerevisiae†

Biochemistry ◽  
2005 ◽  
Vol 44 (39) ◽  
pp. 13163-13171 ◽  
Author(s):  
Wendi Wagner ◽  
Andrew P. Breksa ◽  
Arthur F. Monzingo ◽  
Dean R. Appling ◽  
Jon D. Robertus
Keyword(s):  
Structural Analysis ◽  
Active Site ◽  
Methylenetetrahydrofolate Dehydrogenase ◽  
Active Site Mutants

Structural Analysis of 1-Aminocyclopropane-1-Carboxylate Deaminase: Observation of an Aminyl Intermediate and Identification of Tyr 294 as the Active-Site Nucleophile

2004 ◽  
Vol 116 (26) ◽  
pp. 3507-3511
Author(s):  
Subramanian Karthikeyan ◽  
Zongbao Zhao ◽  
Chai-lin Kao ◽  
Qingxian Zhou ◽  
Zhihua Tao ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Active Site

Inactivation of fumarase by bromomesaconate, an active site-directed irreversible inhibitor

1969 ◽  
Vol 130 ◽  
pp. 688-689 ◽  
Author(s):  
Richard A. Laursen ◽  
Jacob B. Baumann ◽  
Keyes B. Linsley ◽  
Wei-Chiang Shen
Keyword(s):  
Active Site ◽  
Irreversible Inhibitor
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