Applied photophysics offer the following software products:
- Global 3 Analysis Software
- Pro-Data Software Suite
- Pro-K Global Analysis & Data Simulation Software
- Pro-K II - 2nd Order Global Analysis Software
Pro-K IV represents an advance in the analysis capability available to scientists studying wavelength dependent reaction kinetics or time dependant spectra. The introduction of instrumentation capable of generating high quality sets of time dependent spectra comprising many thousand individual absorbance (or fluorescence) measurements has prompted the development of an analysis system which can exploit this data fully and efficiently. The software may also be used to fit single wavelength kinetic data, fluorescence data etc. as well as simulate data based on a given model. The software is user friendly and produces high quality displays of input and output data.
Pro-K IV allows the scientist to globally analyse the complete dataset according to a proposed reaction scheme, providing a best fit parameter set which will accommodate all kinetic behaviour across the entire measured wavelength range.
A key feature of ‘global analysis’ is the optimisation of non-linear reaction parameters (rates) at all measured wavelengths simultaneously. Because individual rates contribute to each kinetic record to differing degrees over the measured wavelength range (depending on the spectral distribution of the reaction intermediates), analysis of all records globally reduces the correlation of these parameters, since events at all wavelengths contribute to the least squares minimisation procedure. This results directly in a more robust fit and the reliable identification of minor intermediates. In addition, Pro-K IV outputs several useful features including calculated spectra for each species and their concentration profiles throughout the reaction.
Global 3 is a global analysis program that is specifically designed for multi-wavelength spectroscopic data, typically protein circular dichroism (CD) or fluorescence spectra, measured as a function of temperature. The CD or fluorescence signature changes with temperature and is indicative of changes in the protein higher order structures. Global 3 calculates the spectroscopic and concentration profiles of all the contributing species as well as the mid-point temperature, Tm, and van’t Hoff enthalpy, HvH, of the transitions between them. It thus delivers structural and thermodynamic data from a single experiment.
Pro-K represents a major advance in the analysis capability available to scientists studying wavelength dependent reaction kinetics or time dependant spectra. The introduction of instrumentation capable of generating high quality sets of time dependent spectra comprising frequently many thousand individual absorbance (or fluorescence) measurements has prompted the development of an analysis system which can exploit this data fully and efficiently.
Pro-K allows the scientist to globally analyse the complete data set according to a proposed reaction scheme, providing a best fit parameter set which will accommodate all kinetic behaviour across the entire measured wavelength range.
Pro-KineticistII is a program whose purpose is the elucidation of reaction mechanisms and their associated parameters from kinetic (multitime) and multi-wavelength spectrophotometric data for reactions carried out in solution. The parameters referred to are the rate/formation constants of the reaction mechanism and proportionality constants or spectra that relate detector response to the concentration of reaction species (eg. molar absorptivity for absorbance measurements). Proportionality constants or spectra are calculated using linear regression and the rate/formation constants are fitted using non-linear regression. Fitting may be carried out on a single spectrum at a single wavelength through to simultaneously fitting to multiple data files each containing kinetic measurements at multiple wavelengths (second order global analysis). There is great flexibility in the reaction mechanisms that may be fitted. In particular reaction mechanisms may contain both steps defined by reaction rate constants and steps defined by formation constants allowing, for example, the inclusion of protonation equilibria steps into a reaction mechanism defining a pH dependent metal-ligand equilibrium.
The Pro-K IV (Pro-Kineticist IV) software is primarily intended for analysis of time dependent spectra generated by the Applied Photophysics SX, Pistar and LKS series of stopped-flow and laser flash spectrometers. Multivariate datasets typically generated using the photodiode array (PDA) detector can be ‘globally’ analysed by fitting the entire dataset to a given model. Additionally, single wavelength data, may be analysed and a facility is available for generating simulated kinetic data. This user guide covers a full description of the installation and use of the software in the analysis of time dependent spectra.
HOS Comparison Suite (qBiC)
Circular dichroism spectroscopy is commonly used to examine the higher order structure (HOS) of proteins as a function of protein source or environment, e.g. wild type or mutant, buffer, excipients, pH, ionic concentration or temperature. It is common practice to assess the degree of similarity visually, but this approach is prone to human errors, and to improve the objectivity of the comparison, numerical approaches to the evaluation of similarity must be used.