The compounds pantoate, HOCH2-C(CH3)2-CHOH-COO-, and sphinganine, CH3-[CH2]14-CHOH-CH(NH2)-CH2OH, are both biosynthesized from the corresponding compounds in which CO replaces CHOH. Use of the prefix 'oxo', which replaces CH2 with CO, would give cumbersome names for such compounds, because it would have to follow the prefix 'deoxy', which replaces CHOH with CH2. Hence we use the prefix 'dehydro' to replace CHOH with CO, as already well established with shikimate and quinate. This is used for dehydropantoate hydroxymethyltransferase (EC 18.104.22.168), newly listed in Supplement 3, and in re-writing the reaction of serine palmitoyltransferase (EC 22.214.171.124) to show that its product is 3-dehydro-D-sphinganine.
1. IUPAC-IUB Joint Commission on Biochemical Nomenclature (JCBN), and Nomenclature Commission of IUB (NC-IUB), Newsletter 1983, Arch. Biochem. Biophys., 1983, 220, 321-324; Biochem. Internat., 1983, 6, following p 128; Biochem. J., 1983, 209, I-IV; Canad. J. Biochem. Cell Biol., 1983, 61, v-ix; Eur. J. Biochem., 1983, 131, 1-3; Hoppe-Seyler's Z. Physiol. Chem., 1983, 364, I-IV; Trends Biochem. Sci., 1983, 8, various issues.
Note The reference to Enzyme Nomenclature and Supplement 3 refers to the 1978 edition not the 1992 edition.