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Table 1.

Measured apparent K_m for exogenous ADP in different permeabilized cell preparations, and diffusion distances from the medium into the center of cells (R_dif)

Preparation	Measured diameter (μm)	R_dif (μm)	Apparent K_m (ADP) (μmol 1^-1)	Reference
Cardiomyocytes	10-25	5-12.5	-	Opie, 1998
	-	-	329±50 ^{^*}	Present study
	16	8	250±38	Saks et al., 1991
	20	10	200-250	Kay et al., 1997
`Ghost' cardiomyocytes	20	10	200-250	Kay et al., 1997
Skinned cardiac fibers	-	-	297±35	Saks et al., 1993
	20	10	300±23	Saks et al., 2001
	-	-	300-400	Seppet et al., 2001
	-	-	370±70	Boudina et al., 2002
	-	-	234±24	Liobikas et al., 2001
	22	11	-	Menin et al., 2001
	-	-	334±48 ^{^*}	Present study
`Ghost' cardiac fibers	20	10	349±24	Saks et al., 1993
	-	-	349±34 ^{^*}	Present study
Skinned cardiac fibers + creatine	-	-	79±8	Saks et al., 1991
	-	-	85±5	Kuznetsov et al., 1996
Rat heart mitochondria in vitro	∼1	0	17.6±1	Saks et al., 1991

Preparation	Measured diameter (μm)	R_dif (μm)	Apparent K_m (ADP) (μmol 1^-1)	Reference
Cardiomyocytes	10-25	5-12.5	-	Opie, 1998
	-	-	329±50 ^{^*}	Present study
	16	8	250±38	Saks et al., 1991
	20	10	200-250	Kay et al., 1997
`Ghost' cardiomyocytes	20	10	200-250	Kay et al., 1997
Skinned cardiac fibers	-	-	297±35	Saks et al., 1993
	20	10	300±23	Saks et al., 2001
	-	-	300-400	Seppet et al., 2001
	-	-	370±70	Boudina et al., 2002
	-	-	234±24	Liobikas et al., 2001
	22	11	-	Menin et al., 2001
	-	-	334±48 ^{^*}	Present study
`Ghost' cardiac fibers	20	10	349±24	Saks et al., 1993
	-	-	349±34 ^{^*}	Present study
Skinned cardiac fibers + creatine	-	-	79±8	Saks et al., 1991
	-	-	85±5	Kuznetsov et al., 1996
Rat heart mitochondria in vitro	∼1	0	17.6±1	Saks et al., 1991

Measured in this work for preparations similar to those described in Fig. 1. The diffusion distances are given to evaluate the rate of Brownian movement of ADP in water, if necessary (Saks et al.,2001).

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