Table 2.

Operons with Average Half-Lives ≤2.5 Minutes

Avg. HL	Operon
1.35	pabA fic yhfG
1.35	yfeC yfeD
1.65	cadA cadBcadC
1.75	deoC deoA deoB deoD
1.95	yhcH yhcl nanE nanT
2.05	ynfB speG
2.1	thrL thrA thrB thrC
2.2	sdhC sdhD sdhA sdhB
2.2	yjbQ yjbR
2.35	lacA lacY lacZ
2.4	folX yfcH
2.45	ybjC mdaA
2.47	nagD nagC nagA nagB

A number of these unstable operons enable biosynthesis that is presumably unnecessary in rich media, such as amino acid biosynthesis (thr, cad), alternative carbon sources (lac, sdh), and nucleotide biosynthesis (deo). Underlining indicates half-lives used in the average.