Table 1.

Relative yields of membrane compartments determined from marker enzymes.

Method	Enzyme	Microsomes	PM Pool	ConA
Affinity	ALP	100		0.55 ± 0.44
	SDH	100		0.37 ± 0.15
	CCR	100		0.37 ± 0.26
Combination	ALP	100	0.7 ± 0.14	0.4 ± 0.17
	SDH	100	0.8 ± 0.07	0.25 ± 0.04
	CCR	100	1.1 ± 0.52	0.1 ± 0.02
Gradient+2PAP (6.3%)	ALP		100	54.0 ± 23.4
	SDH		100	30.0 ± 5.31
	CCR		100	12.9 ± 1.7

Embryos were used as the starting material. Yields of Alkaline phosphatase (ALP; EC 3.1.3.1; PM marker), Succinate dehydrogenase (SDH; EC 1.3.5.1; mitochondrial marker) and Cytochrome c reductase (NADPH) (CCR; EC 1.6.2.4; ER marker). Because significant amounts of ConA elute in the final fraction, specific activities cannot be presented and these figures are raw activity yields, normalized to the activity present in the microsome pellets. Results represent mean ± 1 standard deviation of values obtained from three experiments after adjustment for differences in protein concentration in the microsomal input fraction. The addition of the pre-fractionation by density gradient centrifugation preferentially reduces the amount of contaminating ER in the ConA fraction.