TABLE 1.

Composition of solutions

(A) Solutions used during the experiments
	Na2ATP	MgCl2	EGTA	HDTA	CaEGTA	TES	Na2CP	GSH
Relaxing	5.44	7.70	25	—	—	100	19.11	10
Preactivating	5.45	6.93	0.1	24.9	—	100	19.49	10
Activating	5.49	6.76	—	—	25	100	19.49	10
Rigor	—	3.22	53	—	—	100	—	10
(B) Solutions used to prepare and store skinned fibers
	Na2ATP	MgCl2	EGTA	Imidazole	KP	NaN3	PMSF	Glycerol
Skinning solution	2.5	2.5	5	10	170	—	0.1	—
Storage solution	2.5	2.5	5	10	170	5	—	50%

All concentrations are in mM except glycerol (v/v). ATP, adenosine 5′-triphosphate; EGTA, ethylene glycol-bis-(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid; HDTA, 1,6 diaminohexane-N,N,N′,N′-tetraacetic acid; TES, N-tris[hydroxymethyl]methyl-2-aminoethanesulphonic acid; CP, N-[Imino(phosphonoamino) methyl]-N-methylglycine; GSH, glutathione; KP, potassium propionate; PMSF, phenylmethylsulphonyl fluoride. To all solutions were added 1 mg ml⁻¹ creatine phosphokinase, 10 μM transepoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64) and 20 μg ml⁻¹ leupeptin. pH (adjusted with KOH) was 7.1 at the different temperatures used (A) and 7.0 at 20°C (B). Ionic strength, 200 mM. HDTA was obtained from Fluka (Buchs, Switzerland), all other chemicals from Sigma (St. Louis, MO). In experiments with dextran, 4 g dextran T-500 (Pharmacia Biotech, Uppsala, Sweden) were added to 100 ml solution (4% w/v).