heparan

例句：

1. 1.Heparan is a natural substance found in the human body, playing a crucial role in blood clotting.
   肝素是一种在人体中发现的自然物质，它在血液凝固中起着关键作用。
2. 2.The heparan molecules on the surface of the cell membrane are responsible for binding to proteins and preventing them from moving too quickly.
   细胞膜表面的肝素分子负责与蛋白质结合，防止它们移动过快。
3. 3. In recent years, researchers have discovered that heparan can be used as a drug delivery system to deliver drugs directlyto specific cells in the body.
   近年来，研究人员发现肝素可以作为药物输送系统，直接将药物输送到身体特定细胞。