The cell culture medium comprises {TAIL ~ about 5 to about 150 mM} of {HEAD ~ polar amino acids} 
The cell culture medium comprises { TAIL ~ about 5 to about 150 mM } of { HEAD ~ polar amino acids }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD