Table 1. Final yields of unlabeled and triple-labeled proteins from 50-mL cell cultures: Comparison between high-cell-density and traditional IPTG methods

		Yield (mg)		Molecular weight (Daltons)
Protein		High cell density^b	IPTG^b	Calculated	Measured	%D^c
Triple-labeled
RAP (1-210)	20 ± 3		0.5	33,801	33525 ± 195	~92
RAP (91-323)	25 ± 3		0.8	36,633	36,376 ± 200	~93
ApoE (1-183)^a	18 ± 4		2	22,866	22,686 ± 116	~89
Mouse apoAI (1-216)	15 ± 2		0.8	28,014	27,732 ± 125	~90
Human apoAI	14 ± 1		0.6	32,814	32,401 ± 150	~88

Unlabeled
Human apoAI	34 ± 1		1.0
Human apoE	17 ± 2		0.2

^aApoE (1-183) was expressed in 40% D₂O; the other proteins were expressed in 99.7% D₂O.
^bHigh cell density: high-cell-density expression methods, including auto-induction and high-cell-density IPTG induction; IPTG: IPTG-induced expression. Auto-induction expression was repeated at least three times for each protein; the yield shown is the average ± standard deviation.
^cEstimated percentage of deuteration, assuming 100% ¹³C and ¹⁵N-labeling. For apoE (1-183), the %D is based on 40% D₂O. For all other proteins, the D% is based on 99.7% D₂O.