{HEAD ~ The column} may be closed at the ends and shaken and washed with {TAIL ~ an enzymatic buffer} 
{ HEAD ~ The column } may be closed at the ends and shaken and washed with { TAIL ~ an enzymatic buffer }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL