Table 2 Measurement of MEGS capacity in muscle tissue and enzymatic analysis of the activities of complex V (mtATPase), the respiratory chain enzymes and CS in muscle tissue and fibroblasts

	Muscle tissue	Fibroblasts
[1-14C]Pyruvate + malate*	2.25	ND
[1-14C]Pyruvate + malate-ADP + CCCP†	4.39	ND
ATP production rate‡	22	ND
Complex V, mU/U COX	54 (169 to 482)	122 (209 to 935)
Complex I, mU/U CS	73 (70 to 251)	223 (110 to 260)
Complex II, mU/U CS	518 (335 to 749)	812 (536 to 1027)
Complex III, mU/U CS	3438 (2200 to 6610)	1998 (1270 to 2620)
Complex IV, mU/U CS	2134 (810 to 3120)	797 (680 to 1190)
CS, mU/mg	231 (37.4 to 162)	398 (144 to 257)

CCCP, carbonyl cyanide 3-chlorophenyl hydrazone; COX, cytochrome oxidase; CS, cytrate synthase; MEGS, mitochondrial energy-generating system; ND, not determined.
Figures in brackets are normal ranges.
*Expressed as nmol ¹⁴CO₂/hxmU CS; normal 3.45–7.99.
†Expressed as nmol ¹⁴CO₂/hxmU CS; normal 3.45–7.99.
‡Expressed as nmol (ATP+CrP)/h×mU CS; normal 36–81.7.