FIGURE 2.

Time course for FRET between PLA₂D and PLA₂A during hydrolysis of DPPC liposomes. (A) Emission of PLA₂A at λ = 600 nm (⋄) upon excitation at λ = 460 nm of PLA₂D. Emission of PLA₂D at λ = 520 nm (+) upon excitation at λ = 460 nm. (B) Relative FRET efficiency (○) calculated according to Eq. 3. Conditions were as described for Fig. 1, except for using 32.5 nM of PLA₂D and PLA₂A each. The vertical dashed line marks the burst in activity, with pH shown as solid lines.