it should be noted that one n-acetylgalactosamine in their saccharide chains is alpha-glycosidically linked to another n-acetylgalactosamine by a 1-4 bond and that this is the first example of the presence of an alpha ( 1-4 ) linked galactosamine unit in nature .
C0001055
acetylgalactosamine
C0016943
galactosamine