b'Other gel systems Native gels Zymogram gelsIn native polyacrylamide gel electrophoresis, proteinsInvitrogen Zymogram gels are composed of gelatin and are separated according to the net charge, size, andare used to characterize proteases that utilize gelatin as shape of their native structure. Electrophoretic migrationa substrate, such as matrix metalloproteases, lipases, occurs because most proteins carry a net negativeand other proteases. Samples are run under denaturing charge in alkaline running buffers, with proteins ofconditions, but due to the absence of reducing agents, greater negative charge density migrating faster. At theproteins can undergo renaturation under appropriate buffer same time, the sieving effect of the gel matrix regulatesconditions (e.g., Invitrogen Novex Zymogram Renaturing the migration of proteins according to their size andBuffer). Proteolytic proteins present in the sample consume three-dimensional shape.the substrate in the presence of added divalent metal cations (e.g., Invitrogen Novex Zymogram Developing The Invitrogen NativePAGE Bis-Tris Gel System is basedBuffer). The gels are then stained to generate clear on the blue native polyacrylamide gel electrophoresisbands where the substrate has been digested, against a (BN PAGE) technique developed by Schgger andbackground stained blue. von Jagow, which overcomes the limitations of traditional native electrophoresis by providing a near-neutral operatingHigh-throughput gel electrophoresispH and detergent compatibility. In this specific system,High-throughput gel electrophoresis expands the number the Coomassie G-250 dye binds to proteins and confers aof protein samples that can be analyzed in a given time and net negative charge while maintaining the proteins in theiris especially useful for screening recombination products native state. NativePAGE gels are designed to separateand protein profiling.proteins up to 10,000 kDa.While midi gels enable higher-throughput electrophoresis Because no denaturants are used in the NativePAGEand western blotting than mini gels, the Invitrogen system, protein subunits are generally retained andE-PAGE High-Throughput (HTP) Precast Gel System information can be gained about the quaternary structure.is specially designed for fast, bufferless HTP protein In addition, some proteins retain their enzymatic activityanalysis. Invitrogen E-PAGE gels are self-contained, following separation using the NativePAGE system.precast gels that include a gel matrix and electrodes Tris-glycine and Tris-acetate gel systems can also bepackaged inside a disposable cassette. E-PAGE gels used for native PAGE when used in the absence of SDS inare available in 48-well or 96-well formats. These gels sample and running buffers. use a compact and automated platform, the Invitrogen Mother E-Base Device.IEF gelsIsoelectric focusing (IEF) is a technique designed to separate proteins according to their isoelectric point (pI) rather than molecular weight. The pI is the pH at which a protein has no net charge and no longer moves in an electric field. These gels can be used to determine the pI or to detect minor changes in a protein due to deamination, phosphorylation, or glycosylation. They can also resolve different proteins of similar size that cannot be resolved on standard SDS-PAGE gels. 9'