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Immobilized pH gradients (IPG) simulator ‐ an additional step in pH gradient engineering: II. Nonlinear pH gradients
Author(s) -
Righetti Pier Giorgio,
Tonani Carlo
Publication year - 1991
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.1150121205
Subject(s) - nonlinear system , concentration gradient , immobilized ph gradient , chemistry , chemical engineering , chromatography , physics , engineering , organic chemistry , isoelectric focusing , enzyme , quantum mechanics
Abstract While in the companion paper (Tonani, C. & Righetti, P. G., Electrophoresis 1991, 12 , 1011–1021) we gave the general outline of our new computer program, immobilized pH gradients (IPG) simulator, able to simulate and optimize linear pH gradients for isoelectric focusing in immobilized pH gradients, in the present report we extend the application of such a program to: (i) convex exponential gradients, (ii) logarithmic and (iii) polynomial gradients Program available from Fluka Chemie AG, Buchs, Switzerland . Such gradients are meant to give equal space to protein spots in complex protein mixtures ( e.g. , cell lysates, biological fluids) and follow the statistical distribution of protein p I values along the pH axis. They will prove of fundamental importance in two‐dimensional maps, both because they optimize the spreading of spots in the two‐dimensional plane and because of the excellent reproducibility of immobilized pH gradients. The following concave exponential recipes are given: pH 3–8, pH 3–9, pH 3–10, pH 3–11, pH 4–7, pH 4–8, pH 4–9, pH 4–10, pH 4–11, pH 5–8, pH 5–9, and pH 5–10, as well as the most extended pH 2.5–11 interval. Two interesting logarithmic gradients are described: pH 3–6 and pH 3–7 and one sigmoidal (derived with a polynomial of 5 th degree): pH 3–11.