So once again, we have the meno group found here. We have the sulfate group and we have the carboxylate ion group. Here we have the carboxylate ion group and we have the amino group. And for this particular one, we have the amino group and we have this sulfate group. Now generally speaking, these glycosaminoglycans don't exist by themselves inside our body. Usually the glycosaminoglycans actually covalently associate with proteins to form a category of modified proteins known as proteoglycans.