So, a protein that has tyrosine and it has tyrosine in a position such that it's on the outside of the protein and accessible to chemical reaction can be phosphorylated.

所以,一种蛋白质中含有酪氨酸,并且该酪氨酸位于,像蛋白质的外侧这样的位置,这样才能够发生磷酸化反应

耶鲁公开课 - 生物医学工程探索课程节选

Because these molecules can span across the membrane from outside to inside, they're in just the right position to take messages that they receive from outside the cell and transmit them through the membrane into the cells internal apparatus, and that's what they do.

因为这些分子能穿过细胞膜,连通细胞内外,它们所在的位置非常适于接受信息,它们能将外界获得的信息,通过细胞膜传递给细胞器,这正是它们的功能

耶鲁公开课 - 生物医学工程探索课程节选