This model describes the type II glyceraldehyde-3-phosphate dehydrogenases which are limited to archaea. These enzymes catalyze the interconversion of 1,3-diphosphoglycerate and glyceraldehyde-3-phosphate, a central step in glycolysis and gluconeogenesis. In archaea, either NAD or NADP may be utilized as the cofactor. The class I GAPDH's from bacteria and eukaryotes are covered by TIGR01534. All of the members of the seed are characterized. See, for instance. This model is very solid, there are no species falling between trusted and noise at this time. The closest relatives scoring in the noise are the class I GAPDH's.