Table 1. β-Galactosidase expression observed with the WT or mutant T7 RNAP and with the lac or g10 ITS.

RNAP	ITS	β-Galactosidase, activity*
WT	g10	19,000
I810S	g10	5,300
WT	lac	3,400
I810S	lac	<15
I810S P266L	lac	420

^*Given in nmoles ortho-nitrophenyl-β-d thiogalactopyranoside (ONPG) hydrolized per min per mg of protein.