Figure 2. Hz formation activity in the presence or absence of maltose in vitro.

Ctl - hemin; Mal - Maltose; CF - chromatographic fraction; CF + Mal → H - chromatographic fraction + maltose and hemin added 4 h after starting assay; CF + H → Mal - chromatographic fraction + hemin and maltose added 4 h after starting assay. The assays of Hz formation were carried out for 24 h at 28°C as described in materials and methods. Hz formation activity was expressed as nmol of aggregated heme, during 24 h, for 8 µg protein. The results are the mean and standard deviation of one experiment run in triplicate. The experiment where maltose was added before hemin was significantly different from that with protein alone or that with hemin being added first *(P<0.05).