Table 1.

Glycolipid transfer activity (initial transfer rate) by HET-C2 as a function of pH.

pH	Initial transfer rate of AV-GalCer (pmol/min)*
2	0.75 ± 0.39
3	0.25 ± 0.25
4	1.30 ± 0.08
5	7.78 ± 0.35
6	22.07 ± 0.25
7	16.39 ± 1.46
8	33.70 ± 0.70
9	27.79 ± 1.45
10	3.46 ± 1.04

^*Determined from Förster resonance energy transfer data shown in Figure 5