While synthesis of short polypeptides is a relatively common service offered by more than a few specialized companies, the Protein Expression and Purification Services from New Jersey-based company GenScript Corporation offer an attractive option for protein biologists looking for polypeptides of any length in a competitively priced and professional package.
The protein expression and purification services offered by GenScript afford high-quality custom peptides to academic laboratories with the help of proprietary technologies which assist in creating and stabilizing complex proteins after production. A comprehensive array of production vectors are offered in the protein expression service, including bacterial, yeast, baculovirus, and mammalian systems. After proteins are manufactured in sufficient quantity, the oft-difficult process of dissolving proteins is handled by GenScript’s proprietary FoldArt technology, which guarantees 30-50% solubility of previously insoluble proteins while retaining 85% peptide purity. Additionally, GenScript employs a wide variety of purification methods including affinity column (GST, Ni-IDA, and protein A, G, and L resins), gel filtration, ion exchange, hydrophobic column, and HPLC. In addition to these services, GenScript guarantees protein expression except in the case of protein insolubility, of which the website claims the company will waive all previous charges involved in the synthesis of the product.
Because the creation of sophisticated or highly polar proteins can quickly become expensive, GenScript offers a very comprehensive ordering/quote system which allows the investigator to make adjustments to the final package before confirming the order. Additionally, any samples necessary or helpful in the synthesis of the protein are accepted via parcel services. After completion of the order, the investigator can expect to wait up to 45 days for delivery of the product, depending upon the complexity of the peptide and the quantity of protein requested. Subsequent orders of the same polypeptide from GenScript are conveniently expedited in case the investigator may require more of the purchased peptide.
The quality of the protein products offered by GenScript seems to match or exceed the specifications on its product webpage. In 2007, we ordered several milliliters of a 22 kD protein for in vitro cell culture experiments in which neurons were plated on solubulized, purified target protein and observed for growth. The samples of proteins delivered were marked to be at least 95% pure on the container. We conducted Bradford assays and comparisons of the GenScript produced protein with and independently produced 22kD protein supported the company’s claims. In addition to these tests, the data gleaned from the neuron outgrowth experiment strongly suggested that the GenScript protein samples were inducing the appropriate effect on axonal growth, in reference to previous experiments which utilized verified samples of the proteins.
It is important to note that due to the insoluble nature of the protein, GenScript suspended the peptide samples in detergent, which required thorough dialysis before use with active cell cultures. Storage of the dialyzed and diluted protein involved storage in -80°C freezer, while the stock sample was refrigerated in a 4°C environment. The protein was retained successfully for at least 12 months of the experiment. Throughout the experiment, the 22 kD protein sample produced similar results. Subsequent orders of the same protein arrived within one month of ordering, and were of approximately 95% purity. While not verified, it appears that the samples were not sterilized against growth of bacteria and fungi post-production.
Despite the tradition of isolating peptides in an academic laboratory setting, the Protein Expression and Purification Services offered by GenScript are a powerful and greatly expanded option for investigators interested in procuring all but the most extraordinary custom proteins in excellent purity.