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Origin 7

All new MicroCal calorimetry systems incorporate Origin® 7.0, complete with seven calorimetric models.  Origin is recognized as one of the premier technical graphics software packages as described in PC Magazine, Scientific Computing World, Scientific Computing & Automation Magazine and Scientific Data Management.  Origin 7.0 with its seven calorimetric models is available exclusively from MicroCal.** 

Origin 7 Features List

Enzyme Kinetics Model (for ITC)

This model permits the convenient analysis of data obtained when a substrate solution from the syringe is added to an enzyme solution contained in the sample cell. Fitting such data to a model based on Michaelis-Menten kinetics allows the determination of K_cat and K_m. If the enzyme assay is repeated in the presence of a competitive inhibitor, then the inhibition constant KI can also be determined.

Reference: Todd & Gomez, Analytical Biochemistry 286, 179-187 (2001)

Displacement Model (for ITC)

Doing conventional ITC experiments, it is not possible to accurately estimate binding constants larger than ca. 10⁹ M^-1. However, if a second weaker-binding ligand is added to the macromolecule solution with a strong-binding ligand prior to titration, then binding constants much larger than 10⁹ M^-1 can be determined. This fitting model allows the determination of K_B for the strong-binding ligand as it “displaces” the weaker binding ligand.

Reference: Siguskjold, Analytical Biochemistry 277, 260-266 (2000)

Dimer Dissociation Model (for ITC)

When a dimeric molecule is diluted by injecting from the syringe into a buffer solution in the sample cell, it will tend to dissociate into the monomeric form. This fitting model allows the analysis of heats of dilution resulting from multiple injections, and provides values for both the dissociation constant and the heat of dissociation.

Reference: Burrows et al, Biochemistry 33, 12741-12745 (1994)

DSC Determination of Binding Constant
(for DSC and VP-Capillary DSC Platform)

When T_m is measured in the absence and presence of a ligand, the magnitude of the ligand induced shift in T_m allows one to calculate the ligand binding constant K_B. This model allows the convenient determination of K_B from such data. While the DSC method of estimating K_B is suitable for both weak- and strong-binding ligands, it is particularly appropriate for ultra-tight binding constants too large to measure directly by ITC and other equilibrium methods.

Reference: Brandts & Lin, Biochemistry 29, 6927-6940 (1990)

Determination of Native Protein Stability at Low Temperature (for DSC and VP-Capillary DSC Platform)

Protein stability, customarily expressed as the free energy of unfolding ΔGunf, cannot normally be measured directly at temperatures far below the transition temperature T_m (e.g. 25° C) where the equilibrium strongly favors the native protein. This model allows the estimation of ΔGunf at all temperatures (0° to 90° C) based on values of ΔHunf and ΔCpunf observed at T_m.

Reference: Brandts, Journal American Chemical Society 86, 4291-4301 (1964)

Simultaneous Processing of Multiple DSC Data Files
(for VP-Capillary DSC Platform)

When using instruments with an autosampler, many individual data files can be generated in a short period of time. It is time consuming to handle each data file individually, so routines have been created which allow simultaneous processing of any number of data files. These routines include data entry, baseline subtraction, concentration normalization, determination of T_m values and determination of binding constants when appropriate.

Reference: Plotnikov et al., ASSAY and Drug Development Technologies 1, 83-90 (2002)

**Note: Reseachers requesting Origin 7 for general data analysis (without the calorimetric routines/models) should contact OriginLab directly at: www.originlab.com