Miniaturised immobilised enzymatic reactors can be used for small scale digestion of proteins. There is need for such devices; small scale devices are used either for processing of analytical sample quantities, or as proof of concept before protein digestion at larger scale. This application note compares the performance of a flow through miniaturised immobilised enzymatic reactor (μIMER) with in-solution batch digestion of simple proteins and complex matrices. Automation of peptide analysis by coupled LC-MS is explored as an option to increase throughput. In the cases evaluated, the miniaturised immobilised enzymatic reactor offered comparative results to overnight in-solution digestion, within less than 10 minutes.
Pre-activated CIMmic™ monolithic columns with 100 μL bed volume were immobilised with trypsin from bovine pancreas. This small format allows coupling to HPLC for on-line protein digestion, as well as syringe (manual) operation of the IMER. Pre-treated samples (denatured, alkylated and ultra-filtered) are injected into the column, and the eluate (tryptic digests) are subjected to LC-ESI-MS-MS analysis for protein identification and post-translational modification (PTM) determination.
Coupling trypsin enzyme onto chromatographic supports provides a platform to reuse the enzyme and automate the hydrolysis process. A monolithic chromatographic support, such as Convective Interaction Media (CIM®), enables mass transfer of molecules within its channels exclusively by convective flow. This results in enzymatic conversion which is not limited by diffusion, making CIM® monoliths ideal for the preparation of immobilised monolith enzymatic reactors (IMERs). BIA Separations offers CIMac™ trypsin IMER with a bed volume of 0.1 mL as analytical platform for mass spectrometry (MS)-based proteomics. Larger volume IMERs (up to 80 mL) are available for industrial scale production of protein hydrolysates. The following example describes the enzymatic production of β-Lactoglobulin (β-Lg) hydrolysates using monoliths with 2 μm (N1) or 6 μm (N2) average channel diameter.
Sample displacement chromatography exploits the different relative binding affinities of components in a sample mixture to achieve accummulation of a desired substance on the column before elution. In pharmaceutical applications, requirements for purity and efficacy of plasmid DNA (pDNA) as a therapeutic product are stringent. The separation of linear, supercoiled (sc) and open-circular (oc) pDNA isoforms has already been established on CIM® butyl (C4 HLD) monolithic columns at preprative scale. This process requires high concentration of ammonium sulphate for loading which increases the overall production requirements. Competing adsorption in sample displacement chromatography utilises the binding capacity of the chromatographic resin more efficiently and increases productivity of the chromatographic step.
This application note investigates three monolithic chromatographic supports with different hydrophobicities regarding their applicability for sample displacement of pDNA. CIMac™ C4 HLD (butyl, high ligand density) as a commercial product and pyridine and histamine as custom immobilised columns are compared.
Plasmid DNA (pDNA) as a pharmaceutical product has stringent requirements of purity and efficacy and often one or more chromatographic steps are used in the downstream process. High ligand density butyl-modified chromatographic monolith (CIMmultus™ C4 HLD, part of CIMmultus™ HiP² Plasmid Process Pack™ 1-1, product number 100.0011-2) is currently used in a polishing step of a pDNA purification process (1), is mainly used for separation of supercoiled (sc) pDNA separation from open circular (oc) and linear pDNA isoforms as well as for removal of remaining gDNA and RNA.
This application note presents a comparison of two different polishing processes employing monoliths, namely bind-elute (BE) and the more recently described (2) sample displacement purification (SDP).
DNA immunization can potentially induce both, humoral and cellular immune responses, and thus comprises an attractive approach for the development of an effective vaccine against HCV. The pIDKE2 plasmid is the main component of the CIGB's candidate vaccine against Hepatitis C virus (HVC), which is being used in HCV chronically-infected individuals during clinical trials phase 1 and 2.
In order to satisfy the high demanding plasmids consumption for clinical trials, the downstream process was improved to reach the quantities need it for clinical trials.
As the demand for plasmid DNA (pDNA) based gene therapy and vaccines increases, large scale, cost effective, and reproducible pDNA production will be required. The key to success is a real time in-process control method that ensures a high percentage of supercoiled pDNA in the final product. CIMac™ pDNA Analytical Column allows the monitoring of degradation products (open circular and linear pDNA), the removal of impurities (RNA), and ensures that each production step is yielding the amount of supercoiled pDNA anticipated.