Expert Details
Protein Purification: Hands-on, Over 50 Projects Completed, Over 75 Proteins Purified
ID: 726535
California, USA
Protein purification step is often a bottleneck in most research projects. As a result of working on a variety of different proteins, most of which did not have tags, expert now has the capability of using almost all the known methods of protein purification, particularly those involving conventional low pressure chromatography as well as HPLC. With the knowledge and the actual use of the different chromatography media made by various manufacturers, along with creative modifications to each of the processes used for the purifications, expert can purify some of the most problematic proteins. Expert’s practical experience has benefited clients and more than 50% of his clients have had more than one project after the initial success.
Some techniques of protein purification are capable of giving very good separation but this often requires a significant amount of trial and error. Most research labs have limited resources to pursue such a strategy. Since our focus is primarily on protein purification, we have been able to nail down some of the conditions such that it is now possible for us to obtain high-resolution separations for a variety of different samples. Also, there are too many commercial products to choose from and for a scientist whose goals are different, it is difficult to keep up with latest advances in protein purification.
Starting from the crude extract to the final purified and concentrated form of the protein, many steps are involved and specific expertise is required for each of these steps to ensure that the protein is structurally stable and functionally active. This is particularly challenging when purifying membrane proteins and our expertise has already benefited many research groups in speeding up their projects.
In addition to recombinant proteins from bacterial, yeasts, mammalian and insect cells, expert has purified native proteins from a variety of sources such as, brain, liver, kidneys, serum, placenta, etc. including a variety of different allergens from food.
In brief we can highlight some of the problems experienced by our clients:
Most of them do have some kind of protein purification equipment. They have already tried to purify the protein thinking that a couple of different columns (for e.g., ion-exchange and hydrophobic interaction) along with a sizing column would give them a purified protein of the required purity level. However, after several attempts, they are frustrated since a lot of precious time is wasted and they are still struggling to get over this purification barrier. At this point they decide to call us for assistance and in most cases, because of our expertise, we solve their problem in a few days instead of weeks and months, providing them with a purified protein that they can now use in their experiments.
For a major pharmaceutical company in the Bay area, he scaled up the purification from a few mgs to more than 400 mgs. Five liters culture supernatant was processed, involving multiple chromatographic steps, with final purification and purity testing by reverse phase. This had to be done using prep/semi-prep columns and in a very short period of time to ensure low endotoxin levels and to prevent degradation (a Johnson & Johnson company) He planned a large-scale purification (hundreds of mgs) plus cost-analysis for 16 different allergens from natural sources to a very high degree of purity to be used for developing an allergy related assay (DuPont). Some of these allergens were purified on a small scale to validate the processes.Purified Light Harvesting complexes (LH) or Photosystems (PS) from different sources. These are high molecular weight membrane protein complexes which have to be purified under very low light/green light or dark conditions using a variety of specialized techniques. These highly purified complexes were used for developing solar cells (MIT and Princeton Univ).Because of his expertise in the use of HPLC, he was also able to undertake several research projects (Implant Sciences Corp, Kensey Nash Corp.) in which he conducted Rapamycin elution studies from stents and other materials in a protein-rich medium.He also conducted feasibility studies for Abbott Labs prior to purifying the protein of interest. This project was completed in stages over a period of six months and they were very pleased with our work. For Abbott Diagnostics, he developed a very special purification procedure for a biomarker (from human tissue) with a purity level and activity which exceeded their expectations.
Education
Year | Degree | Subject | Institution |
---|---|---|---|
Year: 1989 | Degree: PhD | Subject: Biochemistry | Institution: State University of New York at Buffalo |
Year: 1981 | Degree: MSc | Subject: Microbiology | Institution: St. Xavier's College, Bombay, India |
Year: 1976 | Degree: BSc | Subject: Microbiology/Chemistry | Institution: St. Xavier's College, Bombay, India |
Work History
Years | Employer | Title | Department |
---|---|---|---|
Years: 1997 to Present | Employer: Undisclosed | Title: President | Department: |
Responsibilities:Expert started the company in 1997 and successfully established a client base providing contract protein purification services to biotech and pharmaceutical companies and academic and government labs. Goal is to provide cost, time and quality benefits to the client using well-designed strategy based not only on the properties of the protein but also on the selection of appropriate purification conditions and chromatography media.He generates new contracts (Marketing, Business Development), plans the entire purification process and conducts the main purification steps keeping in mind the costs, activity of the protein, yields and time constraints. Working on multiple projects - planning, executing and completing the project on time has been a constant challenge and has resulted in significantly increasing our capabilities and expertise. |
|||
Years | Employer | Title | Department |
Years: 2004 to 2006 | Employer: The Scripps Research Institute | Title: Scientific Associate | Department: |
Responsibilities:Cloned, expressed and purified a membrane protein (Connexin 26, which forms a gap-junction channel) from insect cells for obtaining a high-resolution structure. Purification was monitored by electron microscopy using negative staining. The purified protein was used for Single Particle Reconstruction using Electron Cryomicroscopy, 2D crystallization, 3D crystallization and incorporation into nanodiscs.He gained additional experience in working with membrane proteins and the use of state-of-the-art chromatography equipment (AKTA explorer) and Electron Microscopes. |
|||
Years | Employer | Title | Department |
Years: 1993 to 1997 | Employer: PharMingen | Title: Senior Scientist | Department: |
Responsibilities:Developed rapid purification strategies for some of the "hottest proteins" such as IL12, IL5 and IFN-gamma. It was very important to design a fast purification strategy to get enough purified protein for antibody production and enable the company to start selling products associated with the new protein. Worked in the process development group, supervised the work of several technicians and played an active role in Management. Established purification protocols for more than 20 different recombinant cytokines and growth factors. |
|||
Years | Employer | Title | Department |
Years: 1989 to 1993 | Employer: University of Oregon | Title: Postdoctoral Research Associate | Department: |
Responsibilities:Characterized promoter elements that direct transcription by RNA polymerase III in the silkworm. Generated mutant tRNA genes using oligonucleotide-directed mutagenesis and analyzed in vitro properties of these genes. Gained experience in molecular biology techniques including site-directed mutagenesis, cloning in various vectors, sequencing and in vitro transcription. |
Government Experience
Years | Agency | Role | Description |
---|---|---|---|
Years: 1999 to 1999 | Agency: Naval Dental Research Institute | Role: Contract Laboratory | Description: Purification of a recombinant protein involved in tuberculosis |
International Experience
Years | Country / Region | Summary |
---|---|---|
Years: 2002 to 2002 | Country / Region: Italy | Summary: For a scientist at the University of Turin, Italy, he purified a protein, tyrosine kinase, for crystallization. |
Fields of Expertise
chromatography, protein isolation, protein purification method, protein purification, column chromatography, high-performance liquid chromatography, chromatography method development, isoelectric focusing, adsorption chromatography, affinity chromatography, gel electrophoresis, hydrophobic interaction chromatography, ion-exchange chromatography, reverse-phase chromatography, SDS-PAGE, size-exclusion chromatography, cation-exchange chromatography, electrophoretic protein purification, chromatography applications, protein concentration process, enzyme purification, enzyme, protein structure, liquid chromatography, electrophoresis, electrochromatography