Molecular Diagnostics Services, Inc.
A Contract Research Organization

Protein Analysis


MDS offers a variety of characterization assays and product-dependent purification schemes. There are a wide variety of post-manufacturing purification methods available. Proteins A and G are common affinity chromatography columns used as a first step in isolation, although more specific antigen columns can be custom-linked to a support of choice.

Other chromatography options for separation include size-exclusion and weak or strong ion-exchangers, some of which can serve additional purposes such as buffer exchange, concentration, polishing or viral reduction. Nano-filtration, detergent inactivation, low pH and increased temperature are yet other mechanisms available to customers for viral reduction and clearance. Purified antibodies can be forwarded to the customer in bulk solution, vials, or transferred to contracted formulation and filling facilities for further processing or lyophilization. GMP/GLP documentation is provided for manufacturing processes and GLP documentation can be provided upon request for test methods.

GMP/GLP Services: To meet our customer's regulatory and quality requirements, we operate under Current Good Manufacturing Practices (cGMP's). The cGMP procedures, documentation and process controls are required to ensure safe and consistent products. Quality Assurance is responsible for ensuring cGMP compliance. Quality Control ensures that raw materials through final bulk product meet cGMP specifications. Led by experts in the field, MDS can provide a complete proteomic analysis of your samples and offers a range of options spanning sample preparation through to mass spectrometry analysis and N-terminal sequencing of proteins.

Mass Spectrometry: We currently offer accurate and reproducible peptide mass determination by MALDI-TOF mass spectrometry and Q-TOF. The service is completely flexible. We can excise, trypsinize and analyze any number of protein spots from gels. Alternatively we can determine the peptide masses of digested proteins supplied by you.

N-terminal Sequencing: We will sequence proteins supplied in solution or transferred to membrane from the N-terminus to the level you require. For known proteins, a minimum of 5 residues is sufficient. For proteins of an unknown nature, we recommend 15 residues.

Sample preparation and protein determination: Heterologous proteins produced by cells in culture are impure. Cell culture medium components, cellular debris, and cellular proteins are present at higher concentrations in post culture fluids than the desired protein. Removal of cellular debris can be accomplished by many means. However, only a few can be used at large or industrial scale. Our experienced scientists can determine how best to remove debris and other contaminants quickly and efficiently.

Microdialysis: High-salt concentration (phosphates, NaCl, etc.) interferes with protein analysis. This dialysis and concentration step is highly recommended to remove DNA/RNA and prepare samples for isoelectric focusing.

Nuclease treatment: Polynucleotides interfere with isoelectric focusing. Treatment with nuclease removes the interfering polynucleotides.

Enzymatic deglycosylation: This procedure enzymatically cleaves N-linked and sialic acid substituted Gb 1-3GalAca 1 O-linked oligosaccharides from glycoprotein. Enzymatic deglycosylation is less harsh than chemical methods and provides deglycosylated glycoproteins that are suitable for further protein and carbohydrate analysis.

Custom sample preparation: general sample preparation e.g. chunks of tissue, plant leaves, etc.

From your first request for a proposal, a Contract Manager will coordinate with the development scientists and manufacturing, quality and regulatory specialists at MDS to provide a detailed proposal specifically tailored to your requirements.
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©2007 Molecular Diagnostic Services, Inc.