scholarly journals Combination plots as graphical tools in the study of enzyme inhibition

1995 ◽  
Vol 311 (3) ◽  
pp. 981-985 ◽  
Author(s):  
W W C Chan
Keyword(s):  
Enzyme Kinetics ◽  
Dissociation Constant ◽  
Enzyme Inhibition ◽  
Graphical Methods ◽  
Statistical Regression ◽  
Characteristic Appearance ◽  
Mixed Inhibition ◽  
Graphical Tool ◽  
Inhibition Data ◽  
Linear Plot

Although statistical regression has become the method of choice in the analysis of enzyme kinetics, graphical methods continue to be useful on account of their illustrative capabilities. It is pointed out in this paper that enzyme inhibition data may be presented more efficiently as a single linear plot than the traditional way as a family of lines. This approach has been taken previously by Hunter and Downs [Hunter and Downs (1945) J. Biol. Chem. 157, 427-446] but has remained neglected. A new version of this type of plot (combination plot) has been devised which is linear for competitive, non-competitive, uncompetitive and linear mixed inhibition and has a characteristic appearance for each type of inhibition behaviour. The slopes and intercepts not only indicate directly the dissociation constant but also provide quantitative criteria for the nature of inhibition. This plot should serve as a useful graphical tool in enzyme research as well as in biochemical education.

Logistic vs. W-Lambert Information in Modeling Enzyme Kinetics at Quantum Level

2014 ◽  
pp. 1413-1431
Author(s):  
Mihai V. Putz ◽  
Ana-Maria Putz
Keyword(s):  
Enzyme Kinetics ◽  
Absorption Spectroscopy ◽  
Reaction Mechanisms ◽  
Enzymic Activity ◽  
Tunneling Time ◽  
Quantum Level ◽  
Mixed Inhibition ◽  
Time And Energy ◽  
Enzyme Complexes

The logistic temporal solution of the generalized Michaelis-Menten kinetics is employed to provide a quantum basis for the tunneling time and energy evaluations of Brownian enzymic reactions. The mono-substrate and mixed inhibition cases are treated and the associated quantum diagrams of the reaction mechanisms are depicted in terms of intermediate enzyme complexes. The methodology is suited for practically controlling of the enzymic activity throughout absorption spectroscopy.

Analysis of student reasoning about Michaelis–Menten enzyme kinetics: mixed conceptions of enzyme inhibition

2019 ◽  
Vol 20 (2) ◽  
pp. 428-442 ◽  
Author(s):  
Jon-Marc G. Rodriguez ◽  
Marcy H. Towns
Keyword(s):  
Qualitative Study ◽  
Enzyme Kinetics ◽  
Enzyme Inhibition ◽  
Enzyme Inhibitors ◽  
Student Understanding ◽  
Student Reasoning ◽  
Science Practice ◽  
Semistructured Interviews ◽  
Different Types ◽  
Second Year

Student understanding regarding topics in upper-division courses, such as biochemistry, is not well represented in the literature. Herein we describe a study that investigated students’ reasoning about Michaelis–Menten enzyme kinetics and enzyme inhibition. Our qualitative study involved semistructured interviews with fourteen second-year students enrolled in an introductory biochemistry course. During the interviews students were provided an enzyme kinetics graph, which they were prompted to describe. Students were asked to look for patterns and trends in the data and interpret the graph to draw conclusions regarding the types of enzyme inhibition observed, providing the opportunity for the students to engage in the science practiceanalyzing and interpreting data. Findings indicate students were able to attend to the relevant parameters (VmaxandKm) in the graph and subsequently associate changes inVmaxandKmto different types of enzyme inhibitors. However, students expressed difficulty explaining why a specific type of inhibition caused the observed change in the kinetic parameters and there was confusion regarding the distinction between noncompetitive and uncompetitive inhibition. Based on our results, we suggest instruction on enzyme kinetics should emphasize qualitative descriptions of the particulate-level mechanisms related to competitive and noncompetitive inhibition, with less emphasis on discussions of uncompetitive and mixed inhibition in introductory biochemistry courses.

Logistic vs. W-Lambert Information in Modeling Enzyme Kinetics at Quantum Level

2011 ◽  
pp. 168-188
Author(s):  
Mihai V. Putz ◽  
Ana-Maria Putz
Keyword(s):  
Enzyme Kinetics ◽  
Absorption Spectroscopy ◽  
Reaction Mechanisms ◽  
Enzymic Activity ◽  
Tunneling Time ◽  
Quantum Level ◽  
Mixed Inhibition ◽  
Time And Energy ◽  
Enzyme Complexes

The logistic temporal solution of the generalized Michaelis-Menten kinetics is employed to provide a quantum basis for the tunneling time and energy evaluations of Brownian enzymic reactions. The mono-substrate and mixed inhibition cases are treated and the associated quantum diagrams of the reaction mechanisms are depicted in terms of intermediate enzyme complexes. The methodology is suited for practically controlling of the enzymic activity throughout absorption spectroscopy.

scholarly journals Enzyme kinetics: the velocity of reactions

2006 ◽  
Vol 28 (2) ◽  
pp. 36-39 ◽  
Author(s):  
Antonio Baici
Keyword(s):  
Enzyme Kinetics ◽  
Enzyme Inhibition ◽  
Pole Position ◽  
Practical Applications

In the post-genomic world, why are we interested in enzyme kinetics? Judging from the volume of papers published every year, the discipline is far from becoming obsolete. Rather, there is a growing interest spanning from theoretical aspects to practical applications, such as those of pharmacological relevance, with enzyme inhibition in pole position.

A New Non-Radioactive Assay of Phytoene Desaturase to Evaluate Bleaching Herbicides

1996 ◽  
Vol 51 (7-8) ◽  
pp. 534-538 ◽  
Author(s):  
Gerhard Sandmann ◽  
Christian Schneider ◽  
Peter Böger
Keyword(s):  
Optical Absorption ◽  
Enzyme Kinetics ◽  
Absorption Spectra ◽  
Phytoene Desaturase ◽  
Optical Absorption Spectra ◽  
Plant Type ◽  
E Coli ◽  
Inhibition Data ◽  
Radioactive Assay

Abstract A non-radioactive cell-free assay was developed to quantitatively determine inhibition of plant-type phytoene desaturase by bleaching herbicides. An active desaturase was prepared from an appropriately cloned E. coli transformant. Another E. coli transformant was used to produce the required phytoene. Phytofluene and t-carotene, the products of the desaturase reaction, were either determined by HPLC or optical absorption spectra. Enzyme kinetics and inhibition data for the bleaching tetrazole herbicide WL110547 are presented as an example.

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