Enzymatic pathway for the synthesis ofN-acetylgalactosamine, the major carbohydrate portion of the cyst wall. Enzymatic pathway for the synthesis ofN-acetylgalactosamine, the major carbohydrate portion of the cyst wall. Activities for all these enzymes have been shown in reference (203) in a mixture of vegetative and encysting trophozoites, and a proposed pathway was presented. The enzymes are labeled as follows: 1, glucosamine-6-phosphate-isomerase (164,312, 334); 2, glucosamine-6-phosphateN-acetylase; 3, phosphoacetylglucosamine mutase; 4, UDP-N-acetylglucosamine pyrophosphorylase (40, 41); 5, UDP-N-acetylglucosamine 4′ epimerase. Rodney D. Adam Clin. Microbiol. Rev. 2001; doi:10.1128/CMR.14.3.447-475.2001