constitutive

con·sti·tu·tive   (kŏn'stĭ-tōō'tĭv, -tyōō'-)    adj.   Making a thing what it is; essential. Having power to institute, establish, or enact. Of or relating to the synthesis of a protein or an enzyme at a constant rate regardless of physiological demand or the concentration of a substrate. con'sti·tu'tive·ly adv.

Main Entry: con·sti·tu·tive
Pronunciation: 'kän(t)-st&-"t(y)üt-iv, k&n-'stich-&t-iv
Function: adjective
1 a : of, relating to, or being an enzyme or protein produced in relatively constant amounts in all cells of an organism without regard to cell environmental conditions (as the concentration of asubstrate)—compare INDUCIBLE a b : controlling production of or coding genetic information for aconstitutive enzyme or protein <constitutive genes> <constitutive mutations>
2 : being chromatin of a chromosomal region that is condensed intoheterochromatin in all cells of an organism rather than just some —con·sti·tu·tive·ly adverb