The transport activity was saturable with an apparent Km very similar to that of intact Golgi vesicles.

Additional single alanine mutations demonstrated as much as 200-fold increase in apparent K(d) but retained overall protein stability.

The apparent Km values for histidine and phenylalanine were about 0.51 and 1.8 mM respectively.

Thirty-seven peptides bound with apparent K(d) values of 500 nM or lower, with 21 peptides binding better than the GagCM9 peptide.

Asp 120 is also intimately involved in folate binding as increases in the apparent K(d) of up to 15-fold were obtained for the mutants.