-ogen|ədʒɛn|a suffix f. -o + -gen, q.v. In Biochem. appended to the names, usu. terminating in -in, of biologically active compounds, esp. proteins, to form the names of their inactive precursors: as chymotrypsinogen, fibrinogen, pepsinogen, renninogen.1961Rep.Comm. Enzymes Internat. Union Biochem. ix. 49 The names of enzyme precursors should no longer be formed by the use of the suffix ‘-ogen’; the prefix ‘pre-’ should be used instead.
-ogen/əˈdʒɛn/suffix.Form of -gen with -o- provided by first element (androgen, hydrogen) or merely connective (fibrinogen, pepsinogen).