LAL activity in plasma (A) and LAL activity recovery in liver (B) of lal−/− mice that received IP injections of hLAL. Plasma was collected from phLAL- or chLAL-injected mice at 0, 10, 30, 60, 120, 180, and 240 min after injection. Livers were collected at 240 min after injection. LAL activities in plasma and liver extract were determined using 4-MUO as the substrate.