for example , uptake in the ehrlich cell is partitioned between the na+-dependent a system ( which transports a wide spectrum of neutral amino acids ) , the na+-dependent asc system ( which transports alanine , serine , threonine , homoserine , etc . ) , and the na+-independent l system ( which shows reactivity centering around neutral amino acids such as leucine and phenylalanine ) .
C0036720
serine
C0301715
neutral amino acids