Table 1.

Movements Supported by Squid and Bovine Translocators

Sample	Microtubule Movement along Glass	Microtubule Movement in Solution	Bead Movement	Organelle Movementb
Buffer	–	−	–	+
S2 axoplasmic supernatanta	0.44 ± 0.07 μm/sec	+	0.52 ± 0.06μm/sec	+ + + to + + + +
Squid gel filtration	0.35 ± 0.06 μm/sec	+	0.34 ± 0.05 μm/sec	+ + to + + + +
Squid hydroxyapatite	0.37 ± 0.03 μm/sec	+	0.37 ± 0.06 μm/sec	+ + to + + + +
Bovine gel filtration	0.41 ± 0.05 μm/sec	+	0.59 ± 0.01 μm/sec	+ to + +

Microtubule, bead, and organelle movements promoted by S2 axoplasmic supernatant or purified squid or bovine translocator; movement occurred consistently in preparations for which rates are shown. Squid gel filtration peak fractions (n = 7; equivalent to lane 30 in Figure 4) and hydroxyapatite peak fractions (n = 3; equivalent to lane 40, 41 in Figure 5) were tested in motility buffer or 100 mM KCl, 50 mM Tris (pH 7.6), 5 mM MgCl₂, 0.5 mM EDTA, 2 mM ATP at final protein concentrations between 10 and 150 μg/ml. Bovine gel filtration peak fractions (n = 3; equivalent to lane 30 in Figure 7) were tested in KCl/Tris buffer at protein concentrations between 20 and 50 μg/ml. Organelle movement was assessed by viewing a 20 μm × 20 μm field of microtubules for 2.5–15 min and counting the number of different organelles that made directed movements along microtubules. The following rating system was employed: −, no movement in all preparations; +, 0–3 movements/min; + +, 3–7 movements/min; + + +, 7–15 movements/min; + + + +, 15–34 movements/min. The range of organelle movement in different preparations is reported. Microtubule, bead, or organelle movement assays are described in Experimental Procedures.

^aValues from Vale et al. (1985b).

^bThe velocity of organelle movement in all samples was approximately 1.64 ± 0.24 μm/sec.