The overall goal of this procedure is to use HPLC purification to produce high purity amyloid beta 42, and amyloid beta 40 peptides that are capable of forming oligomers.The biochemical properties of the amyloid beta peptide can often make its purification difficult.Therefore, the obtainment of high purity peptide that is capable of oligomer formation can be challenging.This procedure helps to alleviate that challenge.For this HPLC protocol, have prepared stocks of buffers A and B ready as well as the buffer for sample dissolution.To set up the HPLC, first fit the bottles of buffer A and B to the inlets of the pump.Use polymer tubing and one piece fittings and don't mix up the valves.Connect the polymer tubing from the pump outlet to the inlet of the preparative column.Make the one piece fitting finger tight, and make certain the column is in the correct orientation.Now secure another polymer tube from the outlet of the column to the dual wavelength detector.Use finger tight one piece fittings, then, in the HPLC setup software, set the wavelength detector to measure peaks at 214 and 280 nanometers.Next, connect the output valve of the wave length detector to the outlet valve of the HPLC detector using polymer tubing and a one piece fitting made finger tight.This will serve as the sample collection tubing.Now program the HPLC software to run the purification method.From the Set up Instrument Method option, enter the purification method by changing the solvent timetable parameter.Lastly, turn on the HPLC pump from the HPLC software.Now the pump will start supplying the starting ratio of buffer A and buffer B through the preparative column in the HPLC instrument.It is vital to now let the system equilibrate for 30 minutes before proceeding with samples.To begin, dissolve three milligrams of crude A
