Table 2.

Respiratory chain enzyme activities in undifferentiated cybrids. The activities are expressed relative to the mitochondrial matrix enzyme citrate synthase (CS ratio), as percentages of the CS ratio in the parental embryonic stem (ES) cell line

Ratio enzymatic activity	Transmitochondrial cybrid % ratio of parental ES cell line
	CY1‐I	CY2‐I	CY2‐VI	CY3‐I
Complex I/CS	74	71	97	7
Complex II/CS	56	64	132	83
Complex III/CS	83	114	143	89
Complex IV/CS	57	37	37	57