Abstract: A method for determining instrument-dependent parameters of a surface plasmon resonance, SPR, biosensor system, and using those instrument-dependent parameters to measure the concentration of an analyte is provided herein. Also disclosed are methods of monitoring surface binding interactions of the analyte using the instrument-dependent parameters.

Abstract: A method for determining instrument depending parameters of a surface plasmon resonance, SPR, biosensor system is provided. In one embodiment, the method includes the steps of: a) identifying an analyte for use in a calibration step, said analyte having a known molecular weight, a known diffusion constant, a known refractive index increment and a known concentration; b) measuring an active concentration of the analyte by use of the SPR biosensor system according to a known method using the identified analyte and a chip to which the analyte can bind, said known method including the use of an instrument depending constant that is not adopted for each specific instrument, chip and flow cell combination; c) comparing the known concentration of the analyte with the active concentration retrieved in step b); and d) adjusting the instrument depending constant used in the known method for measuring the active concentration according to a result of comparison obtained in step c).

Abstract: A method of determining multimers of a macromolecule monomer in a sample containing the macromolecule comprises the steps of (i) determining the total concentration of macromolecule in the sample, (ii) determining by a biosensor-based detection method, especially mass-sensing, the active concentration of macromolecule in the sample, wherein physical characteristics of the macromolecule monomer are used, (iii) comparing the relationship of determined active macromolecule concentration to total macromolecule concentration for the sample with a corresponding relationship for an at least substantially multimer-free macromolecule-containing sample, and (iv) from a resulting difference determining the presence of multimers in the sample. The method may be used in the purification of macromolecules, such as proteins.

Abstract: A method of determining multimers of a macromolecule monomer in a sample containing the macromolecule comprises the steps of (i) determining the total concentration of macromolecule in the sample, (ii) determining by a biosensor-based detection method, especially mass-sensing, the active concentration of macromolecule in the sample, wherein physical characteristics of the macromolecule monomer are used, (iii) comparing the relationship of determined active macromolecule concentration to total macromolecule concentration for the sample with a corresponding relationship for an at least substantially multimer-free macromolecule-containing sample, and (iv) from a resulting difference determining the presence of multimers in the sample. The method may be used in the purification of macromolecules, such as proteins.

Abstract: The present invention relates to a method for detection of an enzyme-substrate reaction by capturing the product of the reaction on a solid support. More closely, the invention relates to a solid phase system for enzyme characterisation and screening of enzyme-targeted drugs. The method comprises the following steps a) rapidly mixing an enzyme solution with a substrate solution to start a reaction between enzyme and substrate wherein said reaction may result in product formation; and b) monitoring any binding of the product to a capturing agent immobilised on a solid surface, wherein said capturing agent is directed against the product of the enzymatic reaction. In a preferred embodiment the method comprises a further step c) measuring the initial rate of the product binding to the capturing agent and thereby characterize the enzymatic reaction. The method may also be used for drug screening.