{HEAD ~ The methods} involve the use of several sequential steps, including the use of matrices that bind molecules bearing negative charges, matrices that bind molecules bearing {TAIL ~ positive charges}, intermediate selectivity matrices, methods that separate molecules based on their size, shape, or buoyant density, and by affinity purification 
{ HEAD ~ The methods } involve the use of several sequential steps , including the use of matrices that bind molecules bearing negative charges , matrices that bind molecules bearing { TAIL ~ positive charges } , intermediate selectivity matrices , methods that separate molecules based on their size , shape , or buoyant density , and by affinity purification
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH