Table 1. Comparison of methods for prokaryal expression of SeMet-labelled protein.

Met auxotroph, B834	Met inhibition, BL21	No Met inhibition, defined LeMaster medium + SeMet, BL21	Auto-induction, BL21
Slow growth, longer lag phase, low cell density	Closer to LB levels of growth, good cell density	Close to LB levels of growth, good cell density	High cell density, ease of culture, good growth; takes a long time (48 h)
Poor yields, ∼20% that of unlabelled	OK yields, ∼30–80% that of unlabelled	Good yields, ∼50–70% that of unlabelled	Good recovery of protein, often better than induced unlabelled
∼100% incorporation of SeMet	>90% incorporation of SeMet	>90% incorporation of SeMet	>90% incorporation of SeMet