| constitutive | Constantly present, whether there is demand or not. Thus some enzymes are constitutively produced, whereas others are inducible. (18 Nov 1997) |
|---|---|
| constitutive enzyme | <enzyme> An enzyme that is constantly produced by the cell regardless of the growth conditions. Compare: induced enzyme. (05 Mar 2000) |
| constitutive gene | A gene which is continuously expressed without any regulation (transcription can be neither suppressed nor encouraged). These genes generally encode housekeeping functions and are expressed at low levels in all cells. (09 Oct 1997) |
| constitutive heterochromatin | <protein> Regions on chromosomes which are permanently condensed and genetically inactive in every cell in the body. The condensed portions are always in the same position on both homologous chromosomes. An example is the centromeres. Compare: facultative heterochromatin. (09 Oct 1997) |
| constitutive mutant | An organism with a mutation in a regulatory gene, so that the genes which its flawed regulatory product are supposed to suppress become constitutive genes, or impossible to turn off. Thus, the products of the uncontrolled genes are produced to excess. (09 Oct 1997) |