scholarly journals Error structure as a function of substrate and inhibitor concentration in enzyme kinetic experiments

1986 ◽  
Vol 235 (3) ◽  
pp. 797-804 ◽  
Author(s):  
B Mannervik ◽  
I Jakobson ◽  
M Warholm
Keyword(s):  
Kinetic Data ◽  
Initial Velocity ◽  
Experimental Error ◽  
Linear Regression Analysis ◽  
Variable Velocity ◽  
Velocity Data ◽  
Error Structure ◽  
Independent Variables ◽  
Proper Analysis

Optimal design of experiments as well as proper analysis of data are dependent on knowledge of the experimental error. A detailed analysis of the error structure of kinetic data obtained with acetylcholinesterase showed conclusively that the classical assumptions of constant absolute or constant relative error are inadequate for the dependent variable (velocity). The best mathematical models for the experimental error involved the substrate and inhibitor concentrations and reflected the rate law for the initial velocity. Data obtained with other enzymes displayed similar relationships between experimental error and the independent variables. The new empirical error functions were shown superior to previously used models when utilized in weighted non-linear-regression analysis of kinetic data. The results suggest that, in the spectrophotometric assays used in the present study, the observed experimental variance is primarily due to errors in determination of the concentrations of substrate and inhibitor and not to error in measuring the velocity.

scholarly journals Determination of initial velocities of enzymic reactions from progress curves

1986 ◽  
Vol 237 (3) ◽  
pp. 821-825 ◽  
Author(s):  
R Dagys ◽  
A Pauliukonis ◽  
D Kazlauskas ◽  
M Mankevicius ◽  
R Simutis
Keyword(s):  
Initial Velocity ◽  
Experimental Error ◽  
Spline Function ◽  
Present Communication ◽  
Time Value ◽  
Substrate Conversion ◽  
Novel Method ◽  
Cubic Spline Function ◽  
Large Experimental Error

The present communication describes a novel method for estimating initial velocities (v) of enzyme-catalysed reactions. It is based on an approximation of experimental data obtained by the cubic spline function. The initial velocity of a reaction is calculated as a derivative of the approximating function at a time value equal to zero. The proposed method is usable on a computer with a FORTRAN IV program. The method can be successfully used in such cases as substantial extents of substrate conversion, the inactivation of an enzyme in the course of a reaction, the existence of large experimental error or when the reaction mechanism is unknown.

scholarly journals Analisis Kinerja Perangkat Desa di Kabupaten Lumajang

2018 ◽  
Vol 8 (2) ◽  
pp. 42-50
Author(s):  
Moh. Hudi Setyobakti
Keyword(s):  
Work Ethic ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Coefficient Of Determination ◽  
Analysis Techniques ◽  
Independent Variables ◽  
The Government ◽  
The Village ◽  
Two Independent Variables

Village apparatus is an important factor in the running of the government process in the village. Therefore an analysis is needed to determine the factors that affect the performance of the village apparatus. There are two independent variables in this study, namely; work ethic and work discipline. In the process this study uses village tools in Lumajang District as a population with 64 respondents. Furthermore, for data analysis techniques using multiple linear regression analysis, the results of the analysis show that both work ethic and motivation have a significant effect on the performance of the village apparatus. This is supported by the coefficient of determination of 73.4% so that only 26.6% remains for other variables that affect the performance of village equipment. This research is expected to contribute to the development of studies in management science, especially human resource management so that it can become a reference to further research.

scholarly journals Pengaruh Kompetensi, Independensi dan Religiusitas Auditor terhadap Kualitas Audit

2019 ◽  
Vol 6 (01) ◽  
Author(s):  
Timbul Bona Nainggolan ◽  
Suratno Suratno ◽  
Widarto Rachbini
Keyword(s):  
Random Sampling ◽  
Audit Quality ◽  
Linear Regression Analysis ◽  
Total Sample ◽  
Multiple Linear Regression Analysis ◽  
Stratified Random Sampling ◽  
Ministry Of Education ◽  
Probability Sampling ◽  
Independent Variables

ABSTRACT  The purpose of this study was to obtain empirical evidence about the influence of competence, independence and religiosity of auditors on audit quality. Determination of sampling by using probability sampling with the type of proportionate stratified random sampling. The object of this research is auditors in Inspectorate General Ministry of Education and Culture with a total sample of 192 auditors. After the data is obtained, the results will be presented descriptively and analyzed to test the hypothesis. Data were analyzed using multiple linear regression analysis. The results showed that independence had an effect on audit quality, while the competency and religiosity variables had no influence. This study only discusses 3 (three) independent variables that influence audit quality, there may be other variables that can influence. Data in this study were obtained from instruments based on respondents’ answers. This can cause problems, if the respondent’s perception is different from the actual situation. For further research, it is better to understand the meaning of the instrument for measuring the research variables or developing the instruments themselves. ABSTRAK Tujuan penelitian ini dilakukan untuk memperoleh bukti empiris tentang pengaruh kompetensi, independensi dan religiusitas auditor terhadap kualitas audit. Penentuan sampling dengan menggunakan probability sampling dengan jenis proportionate stratified random sampling. Objek penelitian ini adalah auditor di lingkungan Inspektorat Jenderal Kemendikbud dengan jumlah sampel sebanyak 192 auditor. Setelah data diperoleh, hasilnya akan dipaparkan secara deskriptif dan dianalisis untuk menguji hipotesis. Data dianalisis dengan menggunakan analisa regresi linear berganda. Hasil penelitian menunjukkan bahwa independensi berpengaruh terhadap kualitas audit, sedangkan variabel kompetensi dan religiusitas tidak mempunyai pengaruh. Penelitian inihanya membahas 3 (tiga) variabel independen yang berpengaruh terhadap kualitas audit, kemungkinan masih ada variabel lain yang dapat mempengaruhi. Data pada penelitian ini diperoleh dari instrumen yang berdasarkan atas jawaban responden. Hal ini dapat menimbulkan masalah, jika persepsi responden berbeda dengan keadaan yang sebenarnya. Bagi penelitian selanjutnya hendaknya lebih memahami makna dari instrumen pengukuran variabel penelitian atau mengembangkan sendiri instrumen tersebut.

scholarly journals Variabel – Variabel Yang Mempengaruhi Struktur ModalPada Perusahaan Manufaktur Di Bursa Efek Indonesia

2020 ◽  
Vol 1 (1) ◽  
pp. 28-41
Author(s):  
Kurnia Murni Utami ◽  
Diana Dwi Astuti ◽  
Hamzah Fansuri Yusuf
Keyword(s):  
Capital Structure ◽  
Sampling Method ◽  
Stock Exchange ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Manufacturing Companies ◽  
Independent Variables ◽  
Operating Leverage ◽  
Research Period

This study aims to determine the effect of  simultaneous and partial variables of sales stability, asset structure, operating leverage, company size, and profitability on capital structure in manufacturing companies on the Indonesia Stock Exchange. Research period 2014 - 2018. Determination of the sample by purposive sampling method. Using the method of multiple linear regression analysis. The results of the classic assumptions of the study, showed that normally distributed, no multicollinearity, no symptoms of heteroscedasticity, and no autocorrelation. The results of multiple regression, show the independent variables simultaneously influence the dependent variable. Partially, the variables of sales stability, operating leverage and firm size have a significant effect on capital structure, while asset structure and profitability have no significant effect on capital structure.

scholarly journals Analysis of kinetic data for irreversible enzyme inhibition

1989 ◽  
Vol 257 (2) ◽  
pp. 419-424 ◽  
Author(s):  
P J Gray ◽  
R G Duggleby
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Enzyme Inhibition ◽  
Kinetic Data ◽  
Organophosphorus Compounds ◽  
Linear Regression Analysis ◽  
Irreversible Inhibitors ◽  
Progress Curve ◽  
Inhibition Kinetic

Many organophosphorus compounds are irreversible inhibitors of acetylcholinesterase. The methods used in the literature to determine the inhibition kinetic constants usually involve either manual determination of the slope at various points along the inhibition progress curve or fitting polynomials to the curve. The present study investigates the use of non-linear-regression analysis to determine the various parameters. A method is suggested that yields accurate values for the inhibition constants under a range of circumstances.

scholarly journals Estimation of the initial velocity of enzyme-catalysed reactions by non-linear regression analysis of progress curves

1985 ◽  
Vol 228 (1) ◽  
pp. 55-60 ◽  
Author(s):  
R G Duggleby
Keyword(s):  
Linear Regression ◽  
Initial Velocity ◽  
Linear Regression Analysis ◽  
Kinetic Properties ◽  
Progress Curve ◽  
Wide Range ◽  
Non Linear ◽  
Subjective Element ◽  
Zero Time

Most methods for studying the kinetic properties of an enzyme involve the determination of initial velocities. When the reaction progress curve shows significant curvature due to depletion of the substrate, accumulation of inhibitory products or instability of the enzyme, estimation of the initial velocity is a subjective and inexact process. Two methods have been suggested [Cornish-Bowden (1975) Biochem. J. 144, 305-312; Boeker (1982) Biochem J. 203, 117-123] that attempt to eliminate this subjective element. The present study offers a third alternative, which is based on fitting a reparameterized form of the integrated Michaelis-Menten equation to the progress curves by non-linear regression. This method yields estimates and standard errors of the initial velocity and of the time to reach 50% reaction. No prior knowledge of the apparent product concentration at zero time or infinite time is required, since both of these quantities are also estimated from the data. It is shown that this method yields reliable estimates of the initial velocity under a wide range of circumstances, including those where the two previously published methods perform poorly.

scholarly journals DETERMINASI DISIPLIN, KOMPENSASI DAN MUTASI TERHADAP KINERJA PEGAWAI

2019 ◽  
Author(s):  
Surya Akbar
Keyword(s):  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Coefficient Of Determination ◽  
Reliability Test ◽  
Sampling Techniques ◽  
Analysis Method ◽  
Know How ◽  
Independent Variables ◽  
Normality Test

This study aims to identify and analyze the determination of discipline, compensation and mutations one at the same time the performance of employees in the Office of Legislative Secretariat Batam. This study uses three independent variables, discipline, compensation and mutation with one dependent variable namely performance. Usages of variables in this study is expected to know how is the process that occurs and what are the factors driving the creation of a good performance in the Parliament Secretariat Batam. These samples included 66 people who are employees at the Parliament Secretariat Batam.Samples were taken by sampling techniques. Data analysis method used is quantitative analysis, the validity, reliability test, classic assumption test, test multikoloniaritas, heterocedasticity test, normality test, multiple linear regression analysis, t-test, f, test the coefficient of determination R2

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