Figure 7.

Phosphatase-Dependent Degradation of Phospho-Oligosaccharides to Maltose by BAM1.

Phospho-oligosaccharides prepared from potato amylopectin (see “Methods”) were incubated alone (controls) or with the enzyme combinations shown (BAM1-TAP, the TAP-purified LSF1-containing complex; Rec BAM1, recombinant BAM1; Rec SEX4, recombinant SEX4). After incubation, the reactions were stopped by boiling (5 min), and the remaining phospho-oligosaccharides dephosphorylated by treatment with excess recombinant SEX4 (+) or left untreated (−). Free oligosaccharides were analyzed by HPAEC-PAD. No maltose was released from phospho-oligosaccharides by recombinant BAM1 or by the LSF1-containing BAM1-TAP complex. However, coincubation with SEX4 allowed the release of maltose by recombinant BAM1 or by the BAM1-TAP complex. The dashed lines indicate the retention times of linear malto-oligosaccharides with the degree of polymerization indicated.