So on the first sugar, we have the carboxylate group that bears a negative charge and the sulfate group that also bears a negative charge. On the second unit, the second sugar of this disaccharide unit, we also have this sulfate group attached to this carbon, as we have in this particular case. And we have the amino group that also contains this sulfate. So we see that heparin contains many of these negative charges and these negative charges give the heparin its functionality. Now the other three glycosaminoglycans we haven't yet discussed and we're going to focus on them in this lecture. So we have conroytin six sulfate, or simply conjoitin sulfate.