peripheral proteins

Membrane proteins are divided into three classification including Monotypic/Peripheral proteins, Transmembrane proteins and Peptides. Membrane proteins are targets of over 50% of all modern drugs. It is estimated that 20–30% of all genes in most genomes encode membrane proteins. However, such proteins are inherently difficult to purify and characterize. Even when expressed at high levels, the purification is still an urgent issue to handle with and optimize. Surrounding lipids of a membrane protein interfere with both crystallography and Nuclear Magnetic Resonance (NMR) spectroscopy.