FIGURE 1.

Purified ASN12 is taken up and transported by the LDL receptor. A, ASN12 and SN5 were affinity column-purified. Recombinant protein was analyzed by Coomassie-stained polyacrylamide gel. M, marker; RFU, relative fluorescence units. B, recombinant protein was assayed for enzymatic activity with the DAGNP substrate. C, dose response of ASN12 and SN5 protein uptake by serum-starved HepG2 cells. D, diagram of the blood-brain barrier, and E, in vitro system used to examine the rate of protein transport at the blood-brain barrier. F, rates of blood-brain barrier transcytosis of ASN12 and SN5 were calculated with the in vitro blood-brain barrier system. Competition for transport was determined with the LDLR binding GCmB6 recombinant protein.