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SigrafW: An easy‐to‐use program for fitting enzyme kinetic data
Author(s) -
Leone Francisco Assis,
Baranauskas José Augusto,
Furriel Rosa Prazeres Melo,
Borin Ivana Aparecida
Publication year - 2005
Publication title -
biochemistry and molecular biology education
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.34
H-Index - 39
eISSN - 1539-3429
pISSN - 1470-8175
DOI - 10.1002/bmb.2005.49403306399
Subject(s) - nonlinear regression , software , kinetic energy , mathematics , linear regression , curve fitting , nonlinear system , regression analysis , computer science , algorithm , statistics , physics , classical mechanics , quantum mechanics , programming language
SigrafW is Windows‐compatible software developed using the Microsoft® Visual Basic Studio program that uses the simplified Hill equation for fitting kinetic data from allosteric and Michaelian enzymes. SigrafW uses a modified Fibonacci search to calculate maximal velocity ( V ), the Hill coefficient ( n ), and the enzyme‐substrate apparent dissociation constant ( K ). The estimation of V , K , and the sum of the squares of residuals is performed using a Wilkinson nonlinear regression at any Hill coefficient ( n ). In contrast to many currently available kinetic analysis programs, SigrafW shows several advantages for the determination of kinetic parameters of both hyperbolic and nonhyperbolic saturation curves. No initial estimates of the kinetic parameters are required, a measure of the goodness‐of‐the‐fit for each calculation performed is provided, the nonlinear regression used for calculations eliminates the statistical bias inherent in linear transformations, and the software can be used for enzyme kinetic simulations either for educational or research purposes. Persons interested in receiving a free copy of the software should contact Dr. F. A. Leone.